A. s ^ "1%, Division of Agricultural Sciences UNIVERSITY OF CALIFORNIA BEEF CATTLE INVESTIGATIONS on the San Joaquin terimental Range CALIFORNIA AGRICULTURAL EXPERIMENT STATION BULLETIN 765 In rangelands where annual plants make up most of the forage, pasturage is poor in fall and scanty in winter. On such rangelands . . . Can beef cattle be kept in efficient production all year? If so, how much acreage does it take? Which nutrients are deficient in the forage and when? What kind of supplements are needed to make up the deficiencies? How much of them? Will it pay to feed them to a breeding herd? Is heavy stocking or moderate more profitable? Should pastures be used year- long or rotated? Can market cattle be finished on the range? Does it require supplements? What gains can be expected? What type of cattle enterprise is this range best suited to? How much can a herd of ordinary range Herefords be improved by using good purebred sires? To find the answer to such questions, experiments in beef- cattle production were carried out for thirteen years on a Sierra foothill range typical of the "granite" area, where most of the forage consists of annual plants. The data are to some degree applicable to many other areas of annual-type forage. The experiments showed that on this range . . . By using supplements in the fall and winter, a breeding herd could be kept in efficient production year round on about 25 acres per cow. The forage provided enough nutrients while the plants were green, but as plants matured and dried it became deficient in crude protein and low in phosphorus. Scant new forage growth during winter resulted in a deficiency of total energy. The deficiencies could be met by feeding 1 pound of cottonseed cake per cow per day beginning about August 1, increasing this to 2 pounds when the cows began to calve, adding 1 pound of rolled barley after the first rains, and con- tinuing this 3-pound ration until about February 1. Linseed meal could re- place cottonseed cake in the ratio of \ l A pounds to 1. Fishmeal and molasses were also adequate supplements. Feeding an average of 380 pounds of supplements per cow resulted in an av- erage 83 per cent calf crop, the calves averaging 464 pounds at weaning. The unsupplemented herd had a 66 per cent calf crop averaging 406 pounds at weaning. This means 115 more pounds of weaned calf per breeding cow in the supplemented herd, or roughly $1.50 to $2.50 added income for each $1.00 of supplemental feed expense. While heavily stocked pastures produced more beef per grazable acre than moderately stocked ones, the calves were in poorer flesh and worth less per pound. Cows kept yearlong on the same pasture, even through fed supple- ments during the fall and winter, had a lower percentage calf crop and a higher proportion of abortion and stillbirths than those on rotated pastures; but complicating factors make it uncertain whether the differences can be attributed — solely, at any rate — to the grazing practices. Yearlings and 2-year-olds could not be finished for market without feeding them supplements during fall and winter, as well as during the finishing period. The amounts of supplements fed and the gains recorded for cattle marketed at these ages are reported in tables 7 through 11. Data on weaner calves are summarized in table 6. Because of the frequency of poor forage years and the nutritional deficien- cies of the range, this area is considered better suited for breeding-herd produc- tion and raising yearling feeders than for finishing yearlings on the range. The use of Choice purebred bulls plus selection of replacement heifers and culling of cows on the bases of conformation and production records re- sulted in raising the average grade of the herds from Medium and low Good to Choice in eleven years. A table of contents appears on page 71 THE AUTHORS: K. A. Wagnon is Associate Specialist, Department of Animal Husbandry, Davis. H. R. Guilbert was Professor of Animal Husbandry and Animal Husbandman in the Experiment Station, Davis. He died October 17, 1952. G. H. Hart is Dean of the School of Veterinary Medicine, Emeritus, and Professor of Veterinary Medicine, Emeritus, and Veterinarian, Emeritus, in the Experiment Station, Davis. JANUARY 1959 BEEF CATTLE INVESTIGATIONS ON THE SAN JOAQUIN EXPERIMENTAL RANGE K. A. WAGNON H. R. GUILBERT G. H. HART INTRODUCTION Earlier Work on Feeder Cattle in California A he problems of more efficient use of California's rangelands have been dis- cussed since the turn of the century. Gordon H. True, while head of the Di- vision of Animal Husbandry (1914- 1926), made the first, but what proved to be an abortive attempt to study the problems. Through a special legislative appropriation of $50,000. a commercial herd of range cattle was purchased in 1920. Land was leased at Shingle Springs in El Dorado County which car- ried grazing rights on the Peavine Ridge and Wrights Lake areas of the Tahoe National Forest. The project, thereafter, was supposed to be largely self-sustaining — a dubious situation for the launching of any research enterprise. The great drop in cattle prices that shortly followed the initiation of this work soon resulted in depletion of avail- able finances. Professor True's ill health coupled with failure at the time to ap- preciate the importance of the problems led to liquidation of the cattle and lease as a stop-loss procedure. 1 Submitted for publication September 26, 1957. The investigation was ahead of its time and lacked public support. In its broad concepts, future production of feeder cattle on the ranges and the finishing in the valleys on pasture and in feedlots was visualized — a situation that was soon to be realized, but which was very unpopular with cattlemen at the time. Nevertheless, some start was made on obtaining information that soon was required by the industry. Calves and yearlings produced on the foothill and mountain ranges were fattened by the use of concentrates both on irrigated pasture and in feed lots (Howell, 1927). Interrelations of heredity and environ- ment were, perhaps, not fully appreci- ated by the investigators at the time. Probably too great reliance on "good bulls" as a "cure-all" with two little pro- vision for research on environment, par- ticularly specific knowledge of the nu- tritional limitations of the natural for- age, were weaknesses of the original plan. This was a period when California was known as a good place to eat lamb, a poor place to eat beef, and a very poor place to eat pork! Later competition of dressed meat from the Middle West and feedlot finished cattle from Colorado im- ported to meet the demand of a rapidly [4] expanding population accustomed to "quality" beef quickly changed the thinking of producers in this state. Feed- yards were rapidly installed and the quality of beef brought to the equal of that in any part of the country. Establishment of the San Joaquin Experimental Range Federal foresters cooperated in the pres- ent effort to tackle this enormous range problem, particularly E. I. Kotok, who later became Director of the California Forest and Range Experiment Station established by the U. S. Forest Service at the University of California in Berke- ley. It was mainly through his efforts that the Government acquired in 1934 the land at O'Neals, now known as the San Joaquin Experimental Range (Tal- bot, Nelson, and Storie, 1942). The Forest Service then invited the Univer- sity of California to place the livestock on the land and cooperate with them to the extent of carrying out the animal husbandry investigations. When the cooperative agreement was arranged, the University in June, 1935, placed 70 head of grade Hereford 2- year-old bred heifers on the land, and registered purebred bulls were supplied from the University Hereford herd at Davis. One member of the staff of the Division of Animal Husbandry was placed in residence at the Experimental Range. An Advisory Committee of beef- cattle producers representing a wide area in the state, with Harvey Russell of Madera as chairman, was appointed by the Forest Service at the beginning of the work. These men gave valuable aid in the general planning of the proce- dures, and counsel as the experiments progressed. Broad Objectives of the Cooperative Work The general plan of the experiments was subjected to much discussion. Con- sidered was the possibility of moving animals from the Experimental Range to National Forest areas in the high Sierra during the summer — a practice of livestock men long before the U. S. For- est Service was established. On the basis that the cattlemen's investment was largely in these foothill lands and future use of public lands was uncertain, it was finally decided to study means of ef- ficient beef production with the breeding herd maintained year-long on the foot- hill range. The broad objectives were to de- termine the limitations of the natural forage, and to manage livestock opera- tions including the use of supplements to permit the animals to produce the most pounds of meat per acre consistent with maintenance of optimum productivity of the vegetative cover. Data were collected which would permit comparison of the effects of overgrazing on the annual plant growth that predominates in this area with similar information on peren- nial grasses in other regions, which largely formed the basis of the concepts of range management practices advo- cated by professional range managers. An earlier publication (Hutchison and Kotok. 1942) gives a detailed de- scription of the area, outlines the general program and the organization of the work, and reports experimental results of all phases of the project from 1935 to 1940. Studies on the effect of en- vironmental factors, including livestock, on forage production, extending from 1935 through 1948. were also published (Bentley and Talbot, 1951). Some papers dealing with specific phases of the general program are cited later. So**cific Objectives of the Present Studies This publication deals with all phases of the cattle investigations during 1935 through mid 1948, when the experiments herein reported were terminated. These experiments were directed principally toward determining the effects of the un- [5] improved range and of certain manage- ment practices upon percentage calf crop, weight at weaning, growth of young stock, and weight of breeding animals. The management practices studied were mainly (1) feeding ani- mals (both breeding herd and young stock) on range forage alone versus sup- plemental feeding designed to compen- sate for seasonal nutritional deficiencies in the forage; (2) rotational versus year- long grazing; and (3) heavy versus moderate and light stocking. Some tests of different methods of supplemental feeding were included. Another important objective of the in- vestigations was to collect data on the relative advantages, under the conditions of this range, of finishing animals on the range with supplements and of dis- posing of fleshy feeders as calves, year- lings, or 2-year-olds to go into valley feedlots. A third objective was to determine how much the breeding herd, originally of ordinary range quality, could be im- proved by the use of purebred bulls. Although ascertaining causes of cattle morbidity and mortality was not a planned objective of these investiga- tions, experimental conditions afforded an opportunity to collect more complete data on such causes than would be feasi- ble on a commercial ranch, and the in- formation was considered of sufficient interest to include. RESUME OF CLIMATIC CONDITIONS AND FORAGE PRODUCTION The relation of climatic factors, forage growth, and livestock production is an old story to the range stockman. Rain- fall not only varies from year to year, but also varies in wet and dry cycles of several years' duration. The average an- nual range and pasture condition is like- wise quite variable (fig. 1), and while very good and poor forage crops may occur in alternating years, it is also pos- sible to have a series of successive good or poor forage years. Since the range- cattle experiments reported herein are concerned with management procedures year-round upon the same range area, the effects of climatic factors upon the quantity and quality of forage produced are highly important. 90 K k /\ 25 YEAR AVERAGE/ \ A A\^ 80 \ \ 74% y / V /\ / ^"\ A 70 - / v A / "^ ^ \ 60 - / \l V 50 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 L 1 I L ... 1925 1930 1935 1940 1945 Fig. 1. Average yearly range and pasture condition for the San Joaquin Valley area, 1924 through 1948. Data reported by California Crop and Livestock Reporting Service. [6] 14 = Pasture Numbers. ( ) = Pasture Acreages , pproximate for pastures 7 to 14 inc. Corrals and scales. Fig. 2. Pasture diagram of the San Joaquin Experimental Range. Some of the original pastures, designated by numbers, were later divided into north and south, or east and west, sections. [7] The Experimental Area The San Joaquin Experimental Range is an area of about 4,600 acres (Talbot, Nelson, and Storie, 1942) near the center of the state, in the so-called "granite" area of the Sierra Nevada foothills. The land is rolling, exposures in general southwesterly, and the eleva- tion ranges from 700 to 1,700 feet above sea level, with most of the area between 1,000 and 1,500 feet (fig. 2). The area is typical of large areas of the poorer soil types in the foothills throughout the state; it is characterized by frequent granitic outcrops, and the soils are mostly residual and formed from the de- composition of the underlying granitic bedrock. About 12 per cent of the area is in narrow stringer-tvpe swales con- sisting of a darker alluvial soil. Soil depths over much of the area are less than 2 feet. The area is subdivided into a number of pastures (Bentley and Talbot, 1951; Talbot and Biswell, 1942). A study of the effects of different intensities of graz- ing on range and cattle was conducted in pastures 1 to 6. Studies on supple- mental feeding of breeding cows were conducted in pastures 11, 12, 13, and 14. The remaining pastures were used for studies on supplementing weaner calves, pasture finishing, and pasturing of miscellaneous animals. To facilitate the weighing and handling of cattle two corrals were constructed, each with scales, large-animal squeeze chutes, and calf chutes. Vegetation is of the woodland-grass type. The tree and brush cover consists of scattered trees of digger pine, blue oak, interior live oak, and California buckeye, with a variable shrub cover consisting mostly of wedeeleaf ceano- thus and whitethorn ceanothus with con- siderable hollyleaf buckthorn. Other common woody plants are coffeeberry, Mariposa manzanita, elderberry, and poison oak. The herbaceous plant cover consists mainly of annual plants, many of which have been introduced from the Old World. In their study of this forage cover Talbot and Biswell (1942) found that it was composed of over 225 dif- ferent species, but that the bulk of the forage was composed of broadleaf fila- ree, soft chess, and foxtail fescue. Per- ennials, mostly rushes, compose about 3 per cent of the forage cover (Bentley and Talbot, 1951). Bur-clover and redstem filaree, highly valued annual range plants, do not occur in significant amounts. There are, however, several true clovers and a lotus (Spanish clover) that are important constituents of the forage cover. Only two known poisonous plants, Mexican whorled milkweed and durango root (Wagnon and Hart, 1945) , have been found on the area. Rainfall and Temperature The data in figure 4 (pp. 16, 17) show considerable variation in total annual rainfall, with a high of 31.90 inches in 1937-38 and a low of 12.42 inches the fol- lowing season. Marked variations in total monthly rainfall for the same months of the twelve periods may also occur, as shown by a high of 9.94 inches in Janu- ary, 1940, as compared with 0.06 inch for January, 1948. The average annual total rainfall for the twelve seasons re- ported was 19.21 inches, as compared with an estimated average of 17 to 18 inches (Bentley and Talbot, 1951). The curves of monthly mean air tem- perature show considerable similarity for all of the twelve seasons. The monthly mean air temperature fre- quently drops below 50° F in November, where it remains through December and January, frequently through February, and at times even March. In two of the winters, 1936-37 and 1946-47, the monthly mean air temperature dropped below 40° F. In January, 1937, mini- mum temperatures dropped to a low of 16.9° F. [81 Common and Botanical Names of Plants Mentioned Trees and shrubs Blue oak Quercus douglasii California buckeye Aesculus californica Coffeeberry Rhamnus californica supsp. cupsidata Digger pine Pinus sabiniana Elderberry Sambucus glauca Hollyleaf buckthorn Rhamnus crocea var. ilicifolia Interior live oak Quercus wislizenii Mariposa manzanita Arctostaphylos mariposa Poison oak Rhus diversiloba Wedgeleaf ceanothus Ceanothus cuneatus Whitehorn ceanothus Ceanothus leucodermis Broad-leaved herbs and grasses Broadleaf filaree Erodium botrys, and E. obtusiplicatum Bur-clover Medicago hispida Durangoroot Datisca glomerata Foxtail fescue Festuca megalura Maiden clover* Trifolium microcephalum Mexican whorled milkweed Asclepias mexicana Redstem filaree Erodium cicutarium Soft chess Bromus mollis Spanish clover Lotus americanus Spurge Euphorbia ocellata Tomcat clover* Trifolium tridentatum Tree clover* Trifolium cilialatum White-tip clover* Trifolium variegatum *True clovers. Climatic Factors and Forage Growth insure a good germination of the new forage crop. If the initial rain is re- The quality and quantity of feed supply ceived in October, and subsequent pre- varies markedly from season to season cipitation is adequate, a fair amount of according to rainfall and its distribution new forage growth may occur before the in relation to temperature. Nutritional mean air temperature drops below 50° deficiencies constitute a major problem F and retards growth. In general forage of yearlong management of cattle. The growth during the fall and midwinter amounts and time of precipitation and months is slow and uncertain. While also soil temperature are highly impor- snow is rare, winter temperatures fre- tant in the germination of the new for- quently fall below freezing. The value of age crop, as well as its subsequent some old forage left upon the ground growth and species composition. Talbot as a protection to the new forage crop and Biswell (1942) have shown that is well known, and studies (Talbot and about 0.8 inch of rainfall is needed to Biswell, 1942) have shown that under The cover picture shows the contours and cover in the experimental area. [9] moderate grazing, forage growth was usually two or three weeks in advance of that upon closely grazed areas. Rapid forage growth usually starts with rising temperatures, about March 1, and if the soil moisture is adequate the growth may be quite vigorous. Droughty conditions after this time not only restrict forage growth, but may also result in a great reduction of some species such as clovers. The marked ef- fects that fluctuation of rainfall and temperature had upon the composition of the forage cover, for the years 1935 through 1949, are shown by Talbot and Biswell (1942). During this 5-year pe- riod the broadleaved plants varied from 43.5 to 74.8 per cent, the grasses from 20.6 to 55.5 per cent, and the grasslike plants from a trace to 3.6 per cent of the total forage cover. Many of the annual plants may begin to dry the latter portion of April, but here again the rate of maturity and dry- ing are greatly dependent upon moisture and temperature conditions. Rapid dry- ing of the forage usually occurs in May ; however, some green forage is usually available in the swales and upon east- erly slopes through June. Some years, small amounts of green Spanish clover and a small spurge will be available until September. The annual fluctuation of forage pro- duction per grazable acre for the period embraced in this study, is given by Bentley and Talbot (1951). While the average annual production of air-dry forage per acre was about 1,640 pounds, it varied from a low of 1,200 pounds to a high of 2,350 pounds. Detailed data on the variability in length of the "inade- quate green forage period," "adequate green forage period," and "dry forage period" resulting from fluctuations in climatic factors, and on variations in forage production according to range- site classification, are also given. With the complete drying of the for- age cover there is little change in the forage composition except for "weather- ing." If the forage contains a high per- centage of broadleaved plants, many of these will crumble and distintegrate so that their availability to livestock is greatly reduced. Rodents, trampling by grazing livestock, and wind hasten the process. Unseasonal rains upon the dry forage have been found (Guilbert, Mead, and Jackson, 1931) to decrease the nu- tritional value of the forage by leaching constituents of silica-free ash and nitro- gen-free extract. Besides being of re- duced value nutritionally, rained-upon dry forage is usually lowered in palata- bility. It should also be mentioned that the consumption of blue oak acorns by cattle subsisting on the dry range for- age resulted in substantial weight losses (Hart, Guilbert, et al, 1947). Annual plants have the facility of pro- ducing viable seed under quite adverse growing conditions. Studies by Glading, Biswell, and Smith (1940) have shown that in the top % inch of plant litter and soil there was about 334 pounds of seed per acre. Thus it is evident that a more than adequate supply of seed is always available. While heavy germina- tions occur some years, evidence that all the seed does not germinate yearly is demonstrated by the marked variation in species composition of the forage crop that may occur in alternate years, or the heavy forage growth that may occur in a favorable year following a series of droughty years. Seasonal Changes in Chemical Composition of Range Forage Hart, Guilbert, and Goss (1932) study- ing the nutritive value of several of the principal annual forage plants from sev- eral range areas over the state, showed there was a marked seasonal change from a high nutritive value in the early growth stages to a low and often de- ficient nutritive level after drying. They also found that bur-clover and redstem filaree were of higher nutritive value [101 Jan. Feb. Man Apn. Mag Jane Ja/c/ Aag. Sept.. Oct. A/ok Dec. Fig. 3. Seasonal variation in chemical composition of forage samples collected to represent forage grazed by the cattle during 1936 to 1939 inclusive. after maturity than were the majority of annual range plants. Gordon and Sampson (1939) made a similar study of the principal herbaceous plants, as well as the shrubby species, of the ex- perimental area. In order to secure information for this area on the varying seasonal plane of range-cattle nutrition within a single year, and also between years, grazing cows were observed and samples of the forage species being grazed were col- lected and analyzed from 1936 through 1939 (Wagnon, Guilbert, and Hart, 1942) . The graph summarizing the data is reproduced in figure 3. The results indicated that protein content on a dry basis decreased from around 20 per cent early in the season to about 5 per cent by late July, and remained at fairly low levels until late fall. Calcium content, while erratic, was adequate at all times. In one year (1938) phosphorus was probably deficient in late fall. The re- sults of this study and the ones on forage consumption and production were taken into consideration in planning the sup- plemental-feeding program. [in Vitamin A deficiency has been shown to exist upon some California range areas (Hart and Guilbert, 1933) with a resultant lowering of reproductive efficiency of range cows. During the period of this study there have been no manifestations of a deficiency of this essential vitamin in any of the experi- mental groups. The few late-growing herbaceous plants plus a small amount of browse are very likely important sources of vitamin A after the bulk of the forage has matured and dried. Forage Consumption While the above data illustrate the sea- sonal changes in chemical composition of the forage consumed by the cows, they give no information on seasonal fluctuations in their forage consump- tion. The amount of new forage growth during the late fall and winter months is dependent upon the relation of several factors, particularly the amount of new seed germination, temperatures, avail- able moisture, protection by old forage cover, and soil fertility. Immediately after the germination of the seeds the animals concentrate their grazing activi- ties on the new growth even though it may only be about % inch in height. While the cattle avoid the old leached dry forage as much as possible, they are forced to eat certain quantities since the new seedlings usually make the most rapid early growth where protected by some old forage (Talbot and Biswell, 1942). On the other hand, they usually avoid the areas covered by a heavy mat of old forage because so much of the old leached herbage has to be eaten to get a small amount of new succulent growth. While the new forage growth is high in protein and mineral content it is also high in water content. Thus, for varying periods (Bentley and Talbot, 1951) dur- ing the winter months the cattle are feeding upon a forage growth that is not only inadequate in supply, but is also low in total digestible dry matter. In other words, the animals simply do not get enough to eat, even though there may be a superabundance of old dry feed; hence during this period we have a varying deficiency of total energy in- take. Variations in Forage Production While above-average rainfall years often produce above-average forage crops, such is not always the case. Monthly rainfall distribution plus minimum air temperatures have been shown to have a direct influence upon new plant germi- nation and growth (Bentley and Talbot, 1951; Talbot and Biswell, 1942). For example, in the 1936-37 season, with a total rainfall of 23.02 inches and with the monthly mean air temperature dropping to a low of 36.1° F, produc- tion of air-dry forage was 1,400 pounds per acre. In the 1944-45 season, with a total rainfall of 18.98 inches and the monthly mean air temperature dropping to 41.1°, forage production was 2,350 pounds per acre. The 1937-38 season, with the highest total rainfall of 31.90 inches and a monthly mean air tempera- ture low of 43.6° F, produced only 2,200 pounds of forage per acre. GENERAL MANAGEMENT PRACTICES Herds A, B, and C The foundation females for the experi- mental herds consisted of 70 head of 2-year-old, bred Hereford heifers grad- ing Medium to Good. They were pur- chased in June, 1935, and all received supplemental feed during the fall and winter of 1935-36. They calved during October, November, and December. In January, 1936, they were divided into two comparable groups consisting of 33 [12] head each, together with their calves. The plan was to feed supplements to herd A during the latter part of the summer, fall, and winter — the supple- ment period — until green forage would sustain the cows nursing calves. The ob- jective was to feed amounts and kinds of supplements that, together with the range forage available, would meet the minimum nutrient requirement of the cattle for efficient production and repro- duction. Herd B was to serve as a con- trol and subsist on range forage alone except in emergency to prevent exces- sive death loss. Because of the necessity of using these same animals in grazing-intensity in- vestigations, conducted by the U. S. Forest and Range Experiment Station personnel (Talbot and Biswell, 1942; Bentley and Talbot, 1951), the general management of the herds was not strictly comparable with usual prac- tice. From February 1 to August 1 — grazing period — on the average, the cows of both groups ran together, be- ing equally divided among pastures 1 to 6, which varied in size and forage production. The calves were dropped largely during October, November, and December and were weaned and re- moved from the six pastures the first of July at about eight months of age. From August 1 to February 1 (sup- plement period) the two herds were separated and placed in their respective fall and winter pastures. In general herd B had some advantages in amount of dry forage and distribution of north and south slopes. Both herds were al- lowed about 15 acres per head during the period. These pastures were sub- jected to little or no grazing between February and August. Thus the general management was fairlv comparable to a commerical ranch where one portion of the range is used consistently for fall and winter pasture, and another during the growing season and early part of the dry forage period. Because of the experimental design, the cattle could not always be moved to fresh feed when indicated by the condi- tion of the forage or of the cattle, nor could supplemental feeding of herd A always be started as soon as trends in weights showed that it was desirable. Later (1941) herd C was established on the basis of yearlong grazing in one pasture with supplemental feeding com- parable with that for herd A. Culling and the selection of replace- ments are discussed in detail in a later section, "Herd Improvement through Se- lective Breeding." Management practices and experimental methods used only in certain tests are described in connection with the relevant experiments. Supplement-feeding Methods On the basis of the information derived from the seasonal changes in chemical composition of the forage (fig. 3), the condition of the range, and the condi- tion and weight changes of the cattle, an attempt was made to feed the con- centrate supplements to buffer the dif- ference between the more or less con- stant demand for nutrients by the cattle and the variable supply of nutrients from the forage. The general procedure was about as follows: One pound per head daily of cotton- seed cake (43 per cent protein) was fed beginning in August. From the start of calving until the first rains, 2 pounds daily were fed. At the time of the first rains, 1 pound of barley was added, bringing the total supplements to 3 pounds daily. This rate was continued until new forage growth was sufficient to discourage the cattle from coming to the feeding grounds for supplement. The total amount fed varied from 283 to 482 pounds per head according to the l°ngth of the period and the rate of feeding (a heavier rate was required in some years) . The first two calf crops are omitted from the summary because the cows all had similar treatment until after the [13] breeding period for the second calf crop. Thus the effects of the two nutri- tional regimens did not become fully operative until the third calf crop in 1937. Supplements were fed in troughs so as to prevent the loss of fine material. The troughs were so located in the pas- tures that cattle in all parts of the field might hear the feeder calling. It became general practice to call the animals at feeding time, and not round them up, because when the latter method was tried some animals appeared to acquire the habit of waiting for the feeder to come after them rather than responding to calling. Trough space was provided so that the animals were not crowded at feeding. The cattle were fed first thing in the morning. This made it pos- sible to treat sick or injured animals the day found if necessary. It was also easier to take care of calving animals because there was time to hunt them up, if deemed necessary, the first day they failed to report for feeding. Feeding and Conditioning of Bulls In our breeding program it was ncessary to keep breeding records of each bull. Since our bulls were placed with the cows about December 28 when the poor- est forage conditions of the year prevail, and at least two of the bulls were placed with as many as 45 cows each, it was essential that they be in good flesh when turned out. In general the bulls subsisted upon native forage during the green-forage period. After the forage matured and dried they received alfalfa hay free choice, in addition to range forage. From late September until they were turned in with the cows they were fed about 6 pounds of grain mixture per head dailv in addition to alfalfa hay. In order that the younger bulls might get their share of grain it was found neces- sary to feed them apart from the older or more aggressive animals. The bulls do not eat the supplements well when fed with the cows, since they usually take advantage of the daily assembling of the cows to see if any are in heat. The bulls were removed from the cow herd May 1. Weighing Since the animals were weighed indi- vidually frequently throughout the year care was taken in rounding them up and drifting them to the corrals so as to hold handling shrinkage to a minimum. From 1935 through 1939 the animals were weighed on a "full" basis. It was found, however, that the animals did not drink normally when offered water at the corrals before weighing and that there was considerable variation in fill. From 1940 on, in order to reduce the variation as much as possible, the ani- mals were rounded up, allowed to water in field when possible, and drifted to the corrals shortly before nightfall. They were then confined to a corral for the night without feed and water and weighed first thing the following morn- ing. Branding, Castrating, Dehorning, and Vaccinating Calves At the start of our experiments the calves were thrown to the ground and stretched out with ropes for the marking process. Calf chutes (both homemade and manufactured) were shortly added to our corral facilities and it was then possible to mark the calves with con- siderably less labor and gentler han- dling. In general it is our practice to mark the calves by the time the oldest are three months of age. Dehorning was done with either stick caustic or caustic paste throughout the study period. Good results were ob- tained but care must be exercised in the use of the caustic or horn stubs will re- sult. Castration was done by cutting: off the lower third of the scrotum, slitting the [14] membrane covering each testicle, forc- ing out the testicles and severing their cord by scraping with a knife. Branding was not done at the time the calves were marked as they were usually too small for the recorded brand and the individual number branded below the brand. For this reason they were tattooed when castrated and dehorned and then branded with caustic branding fluid about April when the weather was warmer and the calves larger. Vaccinating for blackleg is also done at the time the calves are marked. Blackleg is the only disease for which vaccinating was necessary. At the close of the experimental period vaccinating for brucellosis was initiated as an an- nual practice with the weaner heifers being kept for possible replacements. FORAGE PRODUCTION AS MEASURED BY LIVESTOCK WEIGHT CHANGES Since the weaning of the first calf crop June 30, 1936, a group of unsupple- mented heifers have been raised each year. These heifers were raised as re- placements for the unsupplemented breeding herd, from which they origi- nated and consequently, only the sup- posedly better animals were kept. During the Dry-Forage Period After weaning, the group of heifers was placed in a pasture (a portion of pas- ture 8, 9, or 10, fig. 2) that had not been previously grazed that year. They were maintained here through the dry forage period and the winter period im- mediately following. With the advent of sufficient new forage growth to promote continuous rapid weight gains, the ani- mals were moved to various other pas- tures. An attempt was made to maintain a moderate to light degree of stocking. No supplements other than plain stock salt were fed except for the 1937-38 winter, when it was thought necessary to feed the heifers 1 pound of supplements per head daily over a 48-day period to prevent death losses. The average weight curves of each of the heifer groups raised for the forage years 1936-37 through 1947-48 are presented in figure 4, along with a summation of the total monthly rainfall and monthly mean air temperature for each 12-month period. Each curve is a measure of feed condi- tions as reflected in animal gains and losses. A comparison of the curves indi- cates the variation in feed conditions between seasons and the influence of these upon the animals. As previously stated, the mature dry forage crop, upon which the weaner heifers are first pastured, was produced by the previous growing season. Weight gains during this period, until rains of 0.5 inch or more start new plant germi- nation, are mostly a reflection of the abundance of late-growing green plants such as the perennial rushes in the swales, and Spanish clover and spurge upon the slopes. The marked weight gain of the heifers at the start of the 1938-39 season is a reflection of late forage growth from the preceding wet 1937- 38 season. The heifers made initial weight gains in all the seasons except 1946^7 and 1947-48. The preceding forage grow- ing periods for these two seasons were droughty, and consequently the forage not only dried early but was low in leguminous plants. In addition late rains leached the forage that had dried early. At times a heavy acorn mast will result in marked animal weight losses even though the dry forage is of average value. Thus, in 1937-38, 1940-41, and 1942-43 there were weight losses from the ingestion of live-oak and blue-oak acorns before the advent of new forage [15] growth. In 1943-44 there was a com- bination effect of acorn ingestion and leached dry forage. If fall rains start new forage growth before the acorns drop (1936-37) the green forage offsets the adverse effects of the acorns. In gen- eral, new forage has been started by the time the live-oak acorns begin dropping, but this was not so in 1937-38 and 1943-44. Immediately after seed germination there is a marked reduction in rumen fill 3 (as determined by overnight shrink- age and some paunch measurements) 3 Wagnon, K. A., and H. R. Guilbert. Un- published data. 800 700 600 500 400 800 700 600 500 400 800 700 600 500 400 -80 \ a." 70 2 bJ ■60 H K 50 < 40 z < 30^ 1937-38 10 HEAD j fA W / 7A '/ 17-7 V '/, % Y /< ■80 * 70 ■60 •- 50 i ■40^ 1938-39 6 HEAD 3 !! r7>^m. J I I I L 1940-41 14 HEAD \ V\ rz) / m 7/ i i 1941-42 8 HEAD CO UJ X o 8 E 6 4 Z 2 " 6 7 8 9 10 I I 12 I 234567 6789 10 II 12 MONTH 2 3 4 5 6 7 Fig. 4. The average weight curves of weaner heifer groups for the first year after weaning, with the monthly rainfall total and monthly mean air temperature. No supplements, other than plain stock salt, were fed except for a 48-day period in the 1937-38 winter. [16] as the heifers concentrate their efforts upon the new forage growth. Thus, the actual animal weight losses at this time were exaggerated. During the subse- quent period of uncertain plant growth, livestock weight changes are mostly a reflection of new plant development. But during this period livestock weight losses may also be increased by expo- sure from adverse weather. This oc- curred during the extremely wet 1937- 38 winter. The dry-forage period plus the period of new forage development, up until the new forage growth has developed sufficiently to promote rapid animal 800 I o W 800 700 Q O 00 600 CO § 500 o Q- 400 < DC Ll) > 800 < -80 -70 cl- 700 600 500 400 60 1943-44 10 HEAD 1946-47 9 HEAD 1947-48 9 HEAD 6789 10 II 12 I 2345676789 10 II 12 1234567 MONTH Fig. 4 (continued). For the text of this legend see page 16. [17] weight gains, has been termed the "sup- plement period" in this study. If the heifers suffer marked weight losses, in both phases of the supplement period, as in the 1937-38 season, the total weight loss may be considerable. On the other hand, substantial weight gains may also occur (1939-40). On the average (fig. 4), however, the heifers complete this period of about 7 months weighing about what they did at weaning. During the Green-Forage Period The period from the start of rapid con- tinuous animal gains until their ces- sation with the drying of the forage crop has been termed the "grazing period" in this study. The heifer weight gains during this period are a measure of the growth of the new forage crop, the length of time green forage is avail- able, and to some extent the quality of the forage; since the heifers (fig. 4) were always provided with more than adequate amounts of forage during this period, their weight gains were not a measure of total forage production. Average animal weight gains for the grazing period are variable, as for the supplement period, and range from a low of 219 pounds in the short droughty season of 1946-47 to a high of 347 pounds in the 1944-45 season. Seasonal Total As expected, the average total animal weight gain is quite variable, ranging from a low of 179 pounds in the 1943- 44 season to a high of 366 pounds in the 1944-45 season. SUPPLEMENTED VERSUS UNSUPPLEMENTED RANGE FORAGE FOR THE BREEDING HERD Relation of Plane of Nutrition to Reproduction: Previous Work The relation of plane of nutrition and of deficiencies in specific nutrients to reproduction in cattle has been reviewed by Hart and Guilbert (1923) and by Asdell (1949). Phillips (1949) and Guilbert (1942) reviewed the general relations of diet and reproduction and the endocrine relation involved in nu- tritional reproductive failure. Data col- lected under range conditions have shown that low percentage calf crop generally follows drought years and that wide fluctuations occur that are corre- lated with feed supply and condition of the cattle before and during the breed- ing season. Detailed studies have shown that general undernutrition involving significant weight loss will prevent the occurrence of heat; so will protein, phosphorus, or other deficiences that de- press appetite. In addition to general systemic affect of low energy intake, the evidence indicates that the pituitary pro- duction of gonadotrophins is reduced. Protein and amino acid deficiency may have specific effects in this regard. There is thus a double effect upon the testes and ovaries which makes the re- productive function more sensitive to inadequate nutrition than other physio- logical functions. Since this tends to prevent the onset of reproduction under conditions that might jeopardize the life of both mother and offspring, it prob- ably has value for survival of species in nature and is concerned with the cycles of abundance and scarcity of wild species that are related to the feed sup- ply. There is some indication that the de- gree of negative nutritional balance as well as the actual condition of flesh of the animal is involved in suppression of heat. Thus animals losing weight rapidly on a very poor ration may cease ovulat- ing rather quickly and before reaching a state of emaciation. Very thin animals, [18] on the other hand, may return to regu- lar estrous cycles when returned to a high plane of nutrition and before they reach the condition at which cessation occurred during privation. Lactation in cows constitutes a nutritional drain af- fecting the degree of negative balance or rate of recovery of condition and thus also affects recurrence of heat after parturition. Endocrine relations con- cerned with lactation may also have some suppressing effect. This is a dominant factor in absence of heat during lacta- tion in the pig and rat but evidently is of minor importance in the cow since under favorable conditions most cows will come into heat within 30 to 90 days after calving. Table 1. Effects of Supplemental Feeding upon Reproduction, Weaning Weight, and Production per Breeding Cow Item Herd A, 1937-48 Herd B, 1937-48 Herd C, 1942-48 Supplement program : Average amount fed per cow Average length of period .... 380 lbs.* 175 days 424 lbs.* 187 days Reproduction data, animal numbers Total cow-years Cows culled Replacements : Bred Unbred Total possible pregnancies J Dry cows Pregnancies Deaths : At parturition Other causes Stillbirths and abortions Calf losses before weaning Calves weaned f 478 71 2 88 415 40 375 5 2 20 13 344 469 55 3 75 423 104 319 4 5 21 18 281 163 33 6 37 131 23 108 1 2 15 5 88 Reproduction data, percentages Dry cows, per cent of possible pregnancies Pregnancies, per cent of possible Stillbirths and abortions, per cent of actual preg- nancies Calf losses before weaning, per cent of live births Percentage calf crop : calves weaned as a per cent of possible pregnancies per cent 9.6 90.4 5.3 3.7 82.9 per cent 24.6 75.4 6.6 6.0 66.4 per cent 17.6 82.4 13.9 5.4 67.2 Data on weaned calves Average weaning age Average weaning weight Average pounds weaned calf per breeding cow. 240 days 464 lbs. 385 lbs. 230 days 406 lbs. 270 lbs. 226 days 412 lbs. 285 lbs. * Concentrate supplement. Herd A, during one year when short of natural roughage, was fed an average of 135 pounds of alfalfa hay and 562 pounds of poor-quality grain hay per head. Herd C had 575 pounds of the grain hay per head in addition to concentrates during this year. t Herd B was fed 125 pounds of supplement during a 64-day period in 1937 to prevent excessive death loss. t The discrepancies between total cow-years, total culled, replacements, and possible pregnancies are caused by including records of known abortion or nonpregnant status of cow prior to culling. [19] Table 2. Percentage Calf Crop and Weaning Weight in Relation to Age of Dam on Two Planes of Nutrition Herd A fed supplements, herd B no supplemental feeding Age of cow, Number of cows Percentage calf crop Average weaning age, days Average weaning weight, pounds Production per breeding cow, pounds Herd A Herd B Herd A HerdB Herd A HerdB Herd A Herd B Herd A HerdB 3 4 5 6 7 8 9 10 69 61 80 59 43 31 21 15 64 57 81 60 50 37 21 10 87 82 79 80 88 77 71 100 73 65 59 68 80 68 76 50 240 226 239 241 232 234 245 239 232 221 231 231 229 216 226 257 446 442 469 482 465 466 482 454 406 396 392 426 432 414 416 425 388 362 370 385 409 359 342 454 296 257 231 290 346 281 316 212 Calf Production in Herds A and B The average results for the 11-year period, 1937 to 1947 inclusive, are pre- sented in table 1. Table 2 presents data on percentage calf crop and weaning weight of calves in relation to age of dam for the two planes of nutrition. Figure 5 shows the average weight curves for the herd A and B heifers from prior to first calving to the precalving weight at 5 years of age. Figure 6 shows for cows 5 years old and over the 11-year average yearlong trends in weight curves and the difference caused by supplemental feed- ings. In comparing the performance of herds A and B, the major items of sig- nificance from table 1 are: 1. Fifteen per cent higher pregnancy rate in herd A than herd B. 2. Lower percentage of calves dying between birth and weaning in herd A. 3. Herd A calf crop weaned was 82.9 per cent; herd B, 66.4 per cent, a dif- ference of 16.5 per cent. 4. Heavier calves at weaning from herd A (average difference, 58 pounds per head). 5. The combined difference in calf crop and weaning weight resulted in 115 pounds more weaned calf weight per breeding cow. 6. The results cited above are attrib- utable to the supplemental feeding of herd A, which averaged 380 pounds yearly per breeding cow. 7. From a financial standpoint, the difference in calf production per cow in favor of herd A returned roughly from $1.50 to $2.50 added income for each dollar of supplemental feed expense. Other advantages that accrued from the supplemental feeding program were sta- bilization of the yearly calf crop per- centage and to some extent weaning weight, greater value per pound of the calves, greater weight and salvage value of cull cows, more heifers from which to select replacements, and more accurate selections because of normal growth and development. 8. Calf crop percentage from herd B varied with weather and feed conditions from a low of 55 per cent to a high of 79.4 per cent. The average weaning weight of calves varied from 344 to 466 pounds. Thus yearly production and in- come from this herd was extremely vari- able. [20] 1050 ^900 Q Z g850 o. -800 5 ]750 : 700 650 600 550 ■o • « 2 T> a _ 9- >o «~ — c o< * 2 >A So 7 ill .£ 0> £: c ai » / \ => "Six T3 •> o> a»»- 9 E.S q 0> / \V> / o / •E i?" ^ — / X* X tj / \r o> / " / o /A _ o> / c / o / \i/ £ / / * * / 4) / / ° / E / — / \ I / I U-**- c / A 1 / / o> 1 1 * / / V \ v A- -\ H/ 1 - ? / ' "*«* v / f\ / IN "> / / / in o u ■o c o u v - ™ v / 0> in _ \ / \ / o o V o o " \ / tf) v> V HERD B 1 1 1 1 1 1 1 1 1 Mill 1 l I l I I l l l 1 1 1 1 1 1 1 1 1 1 1 1 Fig. 5. Average weight curves for the herd A and herd B heifers from before first calving to the precalving weight at 5 years of age. 1300 ■p 1250 a. y n — 1200 — 7> — 1150 _ 1 — ^HERD A, FED SUP?' E ME NTs AUGUST F( B'^fftP 1100 c — 01 E 0> N^ EL 1050 a ^ — * ~-"^ z X / «*_ g 1000 • • v v ^^^ — a. >.. \ ? 950 ''* -HERO 8, NO SUPPLEMENTS FED N — . >v • X k X / \ 55 900 • 1 u • t t 850 800 750 N N y S" S s s s s ■ 0> o> D i s a o> 5 . o j "i j> c^ '■5< _ « OX c 01 -o • r t of colvind > l l/i ■o ii a w 700 e c UJ tu 1 3 3) 650 600 1 1 1 L_ 1 1 JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC. Fig. 6. Average yearlong trends in herd A and B weight curves showing the difference caused by supplemental feeding for cows 5 years old and over. [21] Time of Weight Gains in the Breeding Herds The data for the weight curves shown in figures 5 and 6 were taken routinely at the beginning and end of the period during which herd A received supple- ments, at the start of rapid forage growth, at the end of the green forage season, at weaning time, and just before calving began. The weight curves shown in figure 5 and 6 include dry cows as well as those with calves. The dry cows in herd B are much more numerous than in herd A, and since these dry cows of herd B often attained weight and condition exceeding that of herd A cows with calves, the dif- ference in the weight curves are mini- mized. Thus the differences in weight of lactating animals of the two groups are greater than the averages shown in figures 5 and 6. The general trends of the weight curves are similar. They differ, however, in two critical respects. First, the dif- ference in weight, which reflects both growth and condition at the younger ages (fig. 5) and condition of mature animals (fig. 6) . At the beginning of the season of adequate green forage, the disparity in weight between herd A and B heifers averaged 175 to 200 pounds. The lower-weight animals gained faster than their previously supplemented mates during the good forage season so that the weight margin was reduced about one half. For mature cows the corresponding maximum and minimum weight differences between the two groups averaged about 150 and 50 pounds, respectively. Both groups lost an average of about 50 pounds between the weaning of the calves (July 1) and the time cattle were transferred to their fall and winter pastures and supplemen- tal feeding began for herd A. The second factor that is considered critical is that herd A animals, already in good thrifty condition, gained in weight during the last 2 to 3 months before calving whereas herd B cows lost weight during this time. The condition of the animals and the weight attained during breeding season are critical factors affecting the ability of the females to rebreed while still lactating and in the case of heifers, growing as well. Gain in weight during the last third of pregnancy is considered essential to normal udder development and subse- quent lactation. One may postulate that undernutrition inhibits hormone pro- duction or that even in the presence of normal hormonal stimulation an excess of incoming nutrients is essential to realize the udder growth which hormones make possible. The latter hypothesis in- volves the concept of nutrient priorities, more active tissues taking precedence over less active or less vital. In the case under discussion, the rapidly develop- ing fetus appears to have a higher pri- ority than the udder. Whatever the phy- siological explanation, the fact remains that the unsupplemented herd B animals generally were conspicuously lacking in udder development at time of parturi- tion and this was reflected in marked difference in calf gains from birth to four months of age. Calf gains from four to eight months, when milk produc- tion normally declines to low levels in Hereford cows and when the calves are deriving a major portion of their liveli- hood from the forage, were essentially the same for both herds. These results paralleled exactly the detailed studies of sheep by Wallace (1948) at Cambridge University, Eng- land. He found in ewes: (1) that low plane of nutrition throughout gestation resulted in poor udder development and subsequent lactation and lamb gains; (2) that a high plane of nutrition early in gestation and low (resulting in weight loss) during the last third of pregnancy was only slightly better; (3) that a low plane of nutrition early followed by a high plane during the last third of gesta- [22] tion resulted in udder development and lactation equal to or superior to contin- uous high plane of nutrition throughout pregnancy. Thus the actual condition of the animals at parturition was not so important as the shape of the weight curve. The ewes on the high-low and low-high regimens were in about the same condition at lambing but the per- formance of the low-high group was markedly better. This "steaming up" process during the last of gestation has long been an established practice in the dairy industry, and the significance of the principle should be more clearly rec- ognized and applied in practice in meat- animal production. Age of Dam Data on percentage calf crop and wean- ing weight in relation to age of dam on the two planes of nutrition are shown in table 2. The herd was started in 1935 with heifers all of the same age. Culling and replacement was fairly heavy dur- ing the earlier years, not only to im- prove quality, but also to attain a normal age distribution in the herds as rapidly as possible. Neverthless, there is not an even distribution of the various ages for each year; consequently, there are some variations due to season as well as age effects in the data. In both herds the percentage of preg- nancies and calves weaned is lower for second than for first calving, and from the data in table 2 it is apparent that there was also a carryover effect to the third calving in herd B. In herd A the variations from 5 years on appear largely to be caused by seasonal in- fluences and the occurrence in some years of significant numbers of non- specific abortions and stillbirths. The data show that the immature animal hav- ing demands for growth as well as gesta- tion and lactation is more sensitive than the mature to undernutrition as it af- fects reproduction. The calf weights at weaning for the first and second calvings for herd A and the first three calvings for herd B were lower than subsequent calvings. Com- paring these earlier calvings with the peak weights when the cows were six years of age, the difference averaged around 40 pounds less for first calves in herd A, 30 pounds in herd B or about 8 and 7 per cent less respectively. Al- though the weights of calves in the Uni- versity purebred herd at Davis are greater than in herd A, the difference be- tween first and later calves is the same — approximately 40 pounds at 8 months. Knox and Koger (1945), in New Mex- ico, report that first calves averaged 60 pounds lighter than those from mature cows. Knapp, Baker, et al. (1942), in Montana, showed that first calves from 2-year-old heifers were about 50 pounds lighter at weaning than the maximum, which was obtained from cows 5 to 7 years of age. In both cases their more extensive data could be represented by a smooth curve of calf weaning weight from first calves to a maximum at 5 to 7 years, with a decline from 8 years of age onward. The Montana data showed that weaning weight of calves from 10- year-old cows was about the same as from first-calf heifers and at 11 years the weaning weight had declined to about 50 pounds below first-calf heifers. These data have a bearing on culling for age. The general policy practiced bv commercial operators of culling at 9 years appears advantageous both from the standpoint of weaning weight and salvage value of the cows. [23 1 ROTATED VERSUS YEARLONG PASTURES The data for herd C are shown in table 1 along with that for herds A and B previously discussed. Despite sup- plemental feeding of herd C in a man- ner similar to herd A and superior av- erage condition of the cows (part of herd A animals were subjected to re- stricted forage conditions on the six pastures), the average percentage preg- nancies for the seven-year period was 82.4 as compared with 90.4 in herd A. The calf crop weaned was only 67.2 as compared with 82.9 for herd A and in- significantly higher than for herd B, which received no supplemental feed. The stillbirths and abortions comprised 13.9 per cent of the pregnancies as com- pared with 3.7 and 6.0 for herds A and B, respectively. Weaning weights of the calves averaged only 6 pounds more than herd B, a difference of doubtful significance even when the small age difference is considered. In addition to the data cited above there were several calves that for the most part appeared normal at birth but that failed to develop normally. Growth was retarded, the heads tended to be long, the jaw bone appeared straighter than normal, making the muzzle narrow from front to rear. The term "jug head" became applied to them! The possibil- ity that these cases might in some way be a variation of the "acorn calf" was suggested by Hart, Guilbert, Wagnon, and Goss (1947). The animals tended to be narrow in the forerib and to some degree predisposed to bloat. Some of the herd C calves continued to decline or do very poorly for 2 to 3 months after weaning in spite of sup- plemental feeding. A few individuals went into a "decline" that eventuallv resulted in death. The condition, al- though not entirely confined to herd C, has been much more prevalent in this group, confined yearlong to the same field. Similar cases are known to occur in some local commercial herds. [24 An example of the poor response of these calves to supposedly favorable nu- trition is shown by the 1947 data. A calf creep was provided to which the herd C calves had access from March 16 to July 7. The average concentrate consumption per calf was 232 pounds for the period. The calves of herds A and B received no supplemental feed, yet during this time they gained more (275 and 260 pounds, respectively) than those of herd C (231 pounds). These results are difficult to interpret. If some nutritional deficiency or defi- ciencies of a borderline nature exist in the area, it is possible that the practice of yearlong grazing in one area might exaggerate it. For example, it was ob- served that regardless of the general abundance of forage, the cattle tended to concentrate early in the season on swales and other more fertile soil areas. These sites through selective grazing were de- pleted of forage early in the season leav- ing the less favorable sites for use dur- ing the major part of the dry forage period. In contrast with this situation herds A and B were transferred to un- grazed dry forage in August, which pro- vided some selection of forage as well as feed from swales and other superior soil sites. Despite this, the supplemental feeding of herd C made possible the appearance of thrifty condition in the cow herd. Subsequent experiments involving pasture 13 in a two-pasture rotation with pasture 14 did not result in much improvement in production until a com- plete mineral mix was fed. This ap- peared to improve conception and per- centage calf crop, with no detectable improvement in calf weaning weight. There appear to be complicating fac- tors ; and the results with herd C cannot be interpreted as being due solely to yearlong grazing on the same pasture. On natural vegetation alone, confine- ment of cattle on limited areas through- ] out the year may result in underdevelop- ment. Rangelands vary in this respect within short distances. Management has long recognized this in rangeland utili- zation. It was the conclusion of Jones and Love (1945) as a result of an 8-year survey of practices in this state. Because of reorganization of the re- search program in 1948, yearlong grazing in this area (pasture 13) was discontinued and was carried forward on a small scale (12 cows) in pasture 4. The possible role of trace-element defi- ciency is under investigation. GRAZING INTENSITY Methods This investigation involving pastures 1 to 6 (figure 2), constituted initially the principal research project of the U. S. Forest and Range Experiment Sta- tion group in which cattle were em- ployed. It was organized cooperatively with the Animal Husbandry Division of the University of California. Because of the limitations of land and cattle, it was necessary to use the same animals for grazing these areas and for the study of effects of supplemental feeding on year- long cattle management in this foothill area. The primary stated objective was to determine the effect on the range and on the cattle of light, moderate, and heavy or close grazing. Three pairs of duplicate-sized pastures were established in 1935. The approxi- mate acreages were as follows: pastures 1 and 3, 160 acres; pastures 2 and 5, 240 acres; pastures 4 and 6, 320 acres. Subsequently, more detailed surveys gave the total acreages shown in table 3, which also reports swale area and graz- able acreage. The general plan was to stock each pasture with 16 animals so that the rate of stocking would be 10, 15, and 20 acres per head for the small, medium, and large pastures respectively. After pasturing the areas a year or two, it became evident that the forage pro- duction varied widely between pastures and that there were 6 rates of stocking rather than 3 in duplicate. Much of the variation was accounted for by differ- ence in amount of land in swale, tree and brush cover, rock outcroppings, slope exposure, and steepness of slope. As previously discussed, the animals in herds A and B had to be separated in- to different pastures during the late sum- mer, fall, and winter to permit supple- mental feeding of herd A. The season of use of the six grazing-intensity pastures was thus fixed from the time forage had advanced sufficiently to support cows with calves in the medium-sized pastures without supplemental aid to the time when the forage in the most heavily grazed pasture was utilized to a degree designated as "close." Generally this period extended from February to Au- gust and the average time was 182 days. From the forage standpoint, grazing cov- ered the period from before rapid growth, through maturity, to 2 to 3 months after the bulk of the forage was dry. During the first year (1936), each pasture was stocked with 11 cows and their calves, as sufficient numbers were not available to stock at the desired rates. Subsequently each pasture was stocked with 15 head of cows together with their calves and one bull. The bull was removed each year about May 1, and the calves were weaned and removed to other pasture about July 1. The cows on the average remained an additional month, until August 1. Each pair of similar-sized pastures contained either 7 cows from herd A and 8 cows from herd B or the reverse. Tn order that the cumulative effects of the variation in feed supply might be measured, the same [25] cows exclusive of death and culling, were returned to the same pasture each year. Complications in Analyzing Data The use of breeding herds on the grazing- intensity pastures resulted in numerous complications in analyzing and sum- marizing the data. Among these are the following: 1. The gains made by cows while on the several pastures were influenced not only by rate of stocking but also by their treatment during the remainder of the year. Thus, thin herd B cows win- tered without supplement always gained more during the grazing period than herd A cows. This is a factor affecting total gain per head and per grazable acre. 2. While most of the cows had already calved before being placed in the pas- tures, there were a few that calved after- wards and the loss at calving time af- fected the total net gain figures. There were also variables involved with per- centage calf crop, numbers of drv cows, death losses, and so on, not attributable to the experimental procedure but which complicate analysis of results. 3. The segregation of the data into comparable groups reduces the numbers so that the uncontrolled variables cause some erratic differences in the average results. From the animal-husbandry point of view the most important objective of the over-all research program was to learn how to utilize the natural vegetation and to operate a breeding herd on an effici- ent production basis yearlong on the range. That animals do not thrive when they do not get enough to eat was not particularly new information. It was considered, therefore, that the procedure outlined would fairly well fulfill the re- quirements for studying the effect of grazing rate on the range and that the limitations of the cattle data would not detract seriously from the main animal- husbandry objectives. [ Although perhaps not contributing greatly to the store of useful information of the observant operator with long ex- perience on annual-type range, the in- vestigation was important to secure more general recognition that the gen- eralizations derived from experience with perennial-grass ranges did not nec- essarily apply to the annual type. Herd Weights and Calf Production The most important data from the live- stock standpoint are presented in table 3. The data are arranged in order of degree of grazing as revealed by ob- servation and measurement through the years. Except for somewhat lighter average weights of pasture 3 cattle at the time they were placed in the pastures, there was no significant difference in initial weights as related to pasture size or pro- ductivity. Much of the difference exist- ing when the cattle were removed from the pastures was equalized during the time on fall and winter pasture. The principal results shown in table 3 are itemized as follows: 1. With the exception of calves, all categories of herd B animals made greater gains than their herd A mates in the same pasture. This was caused in large measure by the greater initial weight and better condition of herd A animals that resulted from supplemental feeding during the previous fall and winter. 2. Dry cows also gained consistently more than cows with calves. Thus herd B cows that had calves the previous sea- son and failed to rebreed because of in- adequate nutrition and depletion of reserves, regained condition and thrift which enabled most of them to conceive the following year. That the dry cows in herd A were not the result of inadequate nutrition will be shown later. 3. Gains in weight of cows and heifers were restricted in close-grazed pasture 3 and to a lesser extent in pasture 1. 26] This resulted from inadequate forage supply early in the season and from keeping the cattle in the area until dry forage was depleted. At the height of the growing season, production exceeded consumption in all pastures. In other pastures there were no significant dif- ferences in gain related to feed supply. 4. Calf gains were also restricted in pasture 3 under close grazing. Otherwise there was no consistent difference be- tween pastures nor between herd A and herd B calves. As previously discussed, the lighter weaning weight of herd B calves was caused largely by lack of milk during the first 3 to 4 months and Table 3. Effect of Rates of Stocking on Reproduction and on Production, 1937-1947 Average length of period, 182 days, February to August Item Pasture no. and degree of grazing 3, close 1, moderate to close 5, moderate 4, light to moderate light 2, light 51 Stocking and acreage 19.4 18.9 19.7 19.4 19.6 155 154 250 309 316 104 136 162 205 257 8 15 5 6 16 5.4 7.2 8.2 10.6 13.1 Average number of animal units Total acreage Total grazable acreage Acreage in swales Grazable acres per animal unit. 19.6 230 183 20 9.3 Pregnancies and calf crop, in per cent of total possible pregnancies Pregnancies Herd A 88.5 68.6 83.6 61.2 85.5 66.7 73.9 58.7 91.7 78.3 86.7 72.5 91.3 75.8 82.6 66^1 86.9 82.8 80.3 75.7 92.8 Herd B 84.1 Calf crop Herd A 84.3 Herd B 69.8 Average seasonal gains, pounds Cows with calves Herd A 85 147 165 273 153 236 252 227 223 42 138 197 245 299 200 300 283 288 273 38 139 235 219 336 213 279 269 276 287 35 142 205 207 279 187 282 279 272 274 26 166 256 155 357 237 322 268 286 300 23 189 Herd B 236 Dry cows Herd A 297 Herd B 323 Replacement heifers Herd A 226 Herd B 326 Calves Herd A 276 Herd B 292 Gains per animal unit, both herds Gains per grazable acre, both herds 316 34 * Because of the high acreage in swales and the good growth of forage on this pasture, it is considered lightly stocked, even though grazable acreage per unit is moderate. [27] before they were consuming significant quantities of forage. 5. Supplemental feeding of herd A during the late summer, fall, and winter met the conditions essential for concep- tion so that the difference in feed supply on the six pastures did not affect percent- age of pregnancies or calf crop weaned. The imposition of feed shortage early and late in the grazing season, in addi- tion to weight losses suffered by herd B during the fall and winter, resulted in lower conception and calf-crop per- centages in pastures 3 and 1. 6. The over-all result was significantly lower net gain per animal unit in close- grazed pasture 3 and a slight reduction in pasture 1 grazed "moderate to close." The lower gain per animal unit in pas- ture 4 may be explained in part by a large amount of south slope, which pro- vided early feed but which matured and dried early also. 7. Despite the lower gain per animal, the larger number of animals and the complete utilization of the forage in pas- ture 3 resulted in slightly higher live weight gain per grazable acre. Variation of productivity per acre obviously af- fects these data and accounts for the relatively high gain per grazable acre in pasture 2 although much forage was wasted under light grazing. Although pasture 3 shows the highest returns in pounds of gain per grazable acre, it should not be concluded that this is the most profitable use. The cattle were al- ways thinner, the gains contained less energy because of lack of fat, the calves weighed less at weaning, had less bloom, and were worth less per pound. Effici- ency of production for those not re- ceiving supplements was further reduced because of lower calf crops. Figure 7 gives further evidence on the effect of plane of nutrition and the shape of the weight curve upon reproduction and weaning weight of calves. In ad- dition to repetition of the average curves for herds A and B of figure 6, data are shown for herd A and B animals in pas- ture 3, the most heavily grazed pasture. 1300 — 1250 1200 — 1150 1100 < o i-H i-H i-H iH "EL a Eh + + + + + + + + 1 3 tn _ "el "tf OC oo ^ ih eo th ct ^ CO CM I 3 co c: t- in CM CT i-l cc O 00 CM IO K) ^t Z £ IO "<* io c co cc CO ■>* boo efl a. M "" o CO > < .5 CO OC t- CN CM cc t- OC CD t- CO w *» eo cn eo i- 00 OC 00 1- O O CD 3 «* Tjt ^ ^ «tf cc ^ ^J w o ij 8 CO X CD H- CO CO c co • IA "3 -^ 0) s > „ s u J3 .Cj'eS CO c • X ^ CD Pi ca CD CD i-l * «/) o CD T3 >> j> s "3. JS.2 o o o ■* . t- c 00 o o "5"? CN t- CN Ui ■^ "5 3 5 »42 i-l CM iH u s in v. CD c s s * O O iH O l> *tf . Cf> c H 05 O uZ OS CM CM CM io as- o ©« i-H eo CM CM CO 5 CO (1) **• CD CD Tjl ■<* iH CN CM CT. 00 c t- t- CM ■ CM CM iH C Ttf T* T^ cc CO CO -^ c 0) CM CM CM CN CM CN CM CN CM CM CM «*£ E ^ S w 15. a © * *■• OS 00 CM CM CO CN i-l O co co CD CO O cd'5 CM CN CM CN CO CN H H M 3 3 «.a U) 2; co «*■ c (A u a 03 E u Pi & 03 03 03 O TJ 03 >» >> >» S CM 00 1-1 £ -o cB 4 c8 * CO O CM o •a co~ ^ CM CM CM 3. CM of O iH 3 £ OS CM 00~ CO eo "^ "^ o t> co a> 1- CM i-l t- CM CM CM co eo 1 iH 1 1 J rH CM °^ini ic CO • ' « M t- t- ^00 oc 2 OS CTj o o co w co <3 PC \C0 c \W « en CO Ct S < PC \ co co eo t- < (C CO < PC oo < < pcj CO r- t* CD t- pound average gain for the unsupple- mented group. For the subsequent supplemented weaner groups the amounts of supple- ments required are shown in table 4. In the 1937-38 season we had an unusually long supplement period of 243 days, and a total of 597 pounds of supplements per A36-group animal were required to promote average daily gains of 0.58 pounds, with a maximum daily intake of 5 pounds of supplements per head when the most adverse conditions ex- isted in the winter. Marked ill-effects re- sulted in the B36 group and it was con- sidered necessary to feed them 1 pound of supplements per head daily for 48 days to prevent death losses. They com- pleted the supplement period with an average weight loss of 58 pounds from their weaning weights. As previously stated, the ingestion of live oak acorns before the first fall rains and exposure from the very wet winter contributed to the weight losses of the B36 group. In contrast to this severe 1937-38 winter situation, the 1939-40 supple- ment period lasted 225 days and a total of 286 pounds of supplements were re- quired per A38 group animal to produce an average daily gain of 0.55 pound. The B38 group animals finished the pe- riod with an average total gain of 51 pounds over their weaning weight. The 1940-41 supplement period was another winter of adverse feed conditions in that live oak acorns were again eaten by the calves. The A39 group calves were fed a total of 399 pounds of supplements per head over a 205-day period but did not reach the goal of V2 pound average daily gain. In feeding the A39 group they were divided into two comparable groups (A39/1 and A39/2) at the be- ginning of the supplement period. The A39/1 group was supplemented with cottonseed cake and rolled barley in the previously described manner, whereas the A39/2 group received only cotton- seed cake in similar total amounts. As shown by table 4, there was no signifi- cant difference in their gain. In the 1938-39 supplement period the A37 group were fed fishmeal and mo- lasses as supplements. Good-quality fish- meal was readily available at the time and there was a desire to investigate the possibility of self-feeding the fishmeal mixed with molasses. The mixture proved quite palatable, and daily consumption increased to about 9.5 pounds per head with resultant poor utilization of dry range feed and some bloating. It was therefore necessary to resort to hand- feeding, and it was found the calves would readily eat the fishmeal alone. Average daily weight gains of 0.68 pound for the A37 group were com- parable to what might be expected from feeding cottonseed cake and rolled barley. The B37 group only made aver- age total gains of 7 pounds above their weaning weight, which indicates an about-average supplement period. These data indicate the necessity of a flexible supplemental feeding program capable of rapid adjustment to meet changes in the nutritive value of the natural range feed during the supple- ment period. Feeding for 1 to 1 Va Pounds Daily Gain In the above studies we have been con- cerned with promoting average daily gains of V2 to % pound in weaner calves through their first supplement period. Studies were also conducted to ascer- tain the supplements required to pro- mote average gains of 1 to 1% pounds per head daily. Some of these steers were to be used later in studies on finishing yearling cattle upon the range. Beginning with the 1940 calf crop all the steer calves were combined to form experimental groups. Combining steer calves from the unsupplemented herd with those from the supplemented herd created greater variation within the [34 U) c o o c o E a 3 *5 o 3 boo si 73 * *«1 !T3 «5 o w o as 1 * SI* > OJ 0) 3£ 6 d CD CD IO O C- o O rH O IO 00 O 6 rA CO OS rH !2 Z2 rH < < CO »H CO 7 r£c£ ^ 3 3 CI © 8*2 9J ** |9 is tn 5 • 2 cn^ 4 to 4) 3 3 J3 £ o £5,5 G O o E 0) Q. Q. 3 V) u O LU c o o Q *^ o X s E E 3 EC CO o s « beg V o. bo (4 h > to a Q -0.05 -0.05 +0.57 +0.56 +1.03 "3 O © rH ^ O t- rlH CN II + + + bp '3 co ►1

< "5 3 E *tf C* tH (N 00 H C5 © t- 00 ■<* CO CO UO CO "3 s 'S (9 ft ■e.3 «1 £> o C ft 0) . B*S * o a* 3 oa It %1 * * -J— ++ • • tH OS O • • "* CO (N §T3 CD S cp eg O to O * * -t— ++ 00 CO ^* • • CO 00 o • • tN CN ■«* SoS CO O ^ Gi CO Average length of period, days O) CO 00 CO Oi i-H iH iH *H CO > o hi V s a a "0 i a x" V CO o* o a a c3 ft bo 1 CD CD h OS ot i- ■s «< 5 • a: P. 03 P tl3 CO « O W ft .a >-. ft CD « tuD I " 2 «a \so > cn\ q *"^ 05 o ® s CD > 1 tH tH . t/3 43 •S3 two >> CO » » ec3 ^^ - >-< o « n-i a "g w > groups, as well as lowering average initial weight. Unsupplemented groups of heifers continued to be carried each year to provide replacement heifers for the B herd and also to provide a yard- stick of the supplement and grazing pe- riods that followed their weaning (fig. 4) . Some steers of the 1940 calf crops were used in an experiment on the im- portance of continuous growth in beef cattle, which has been reported in detail (Guilbert, Hart, et al, 1944). The re- maining steers were supplemented for moderate continuous gains and required a total of 489 pounds of supplements per head for average daily gains of 0.55 pound over a 246-day period. Weaner steer groups from the 1941, 1942, 1944, 1945, and 1946 calf crops were used to study the amounts of sup- plements required to promote average daily weight gains of 1 to 1% pounds as compared with gains of % to % pound. A summation of these data is presented in table 5. (All but a few heifers of the 1943 calf crops were sold at weaning.) In supplementing for 1 pound average daily gains the initial daily ration was 2 to 2% pounds of supplements per head. During the most adverse forage conditions of the winter the daily ration was increased to 4 to 5 pounds daily per head. In general the maximum amounts of cottonseed cake fed daily per head varied from IV2 to 2 pounds with the balance of the ration rolled barley. As shown by the data in table 5, not only were the supplement periods longer but also 43 to 61 per cent more feed was fed per pound of gain than for V2 to % pound daily gain. Because of the adverse forage conditions and lack of sufficient animals to furnish the desired steer groups, the 1942 groups were not fed for the gains attained in the other groups (table 5). Table 6 gives a summation of the data on weight gains or losses with and with- out supplements for weaner calves for [36 the supplement period after weaning. These data show that with an average supplement period of about 217 days, weaner calves not supplemented had an average weight loss of about 10 pounds, whereas weaner calves fed an average total of about 416 pounds of supple- ments made total average gains of 122 pounds. On the other hand, when aver- age gains of about a pound daily were aimed for, an average total of 824 pounds of supplements per calf over a 239-day supplement period was required. Gains during the Grazing Season The dry-forage and winter seasons are usually the most costly for producing weight gains. Animals in good flesh will gain less on good forage than will thinner cattle that lost weight, or made little gain, in the previous adverse-for- age period. Since most cattle are sold at the end of the good-forage period, rather than at the close of the supple- ment period, the net value of supple- mental feeding calves or yearlings is best judged at the close of the good- forage period after the supplement period. The problem is to secure eco- nomical gains during the high-cost sup- plement period without subsequently minimizing cheaper grazing-period gains. Data used in this discussion are the records of groups of weaners that were supplemented for average daily gains of % to % pound during the supplement period and then carried through the following grazing period on forage alone. Comparably aged unsupple- mented groups of weaners that were carried through both forage periods on forage alone are shown for comparative purposes. The data are limited because Table 7. Weight Gains for Supplemented and Unsupplemented Yearlings on Good Pasture after the Poor-Forage Period Sex, period, group, and treatment during poor-forage period Number of animals Average weight, pounds Initial Final Average gain, pounds Total Daily Steers 12/29/36-8/4/37, 218 days A35, supplemented B35 unsupplemented 2/6/,40-7/31/40, 175 days A38, supplemented B38, unsupplemented Heifers 1/29/41-8/12/41, 195 days A39, supplemented B39, unsupplemented 2/26/43-6/28/43, 122 days A41, supplemented B41, unsupplemented 3/10/44-7/11/44, 123 days A42, supplemented B42, unsupplemented 1/20/45-7/10/45, 171 days A43, supplemented B43, unsupplemented 14 14 15 16 579 447 626 450 890 786 909 778 311 339 283 328 1.43 1.55 1.62 1.87 10 15 13 11 15 10 5 5 587 415 590 403 570 360 597 382 825 714 785 639 762 588 872 726 238 299 195 236 192 228 275 344 1.22 1.53 1.60 1.93 1.56 1.85 1.61 2.01 [37 of finishing experiments. The data are presented in table 7. The grazing period varied from 122 to 218 days. In each case the unsupplemented groups out- gained the heavier-fleshed animals that had been supplemented the previous pe- riod, but in each year they failed to attain the degree of fleshing attained by the latter animals. Since the A35 and B35 groups of steers were of similar fleshing at the time of weaning, a com- parison of the weight changes of these two groups through the two major for- age periods is representative. The A35 group steers made a total average gain of 124 pounds in the supplement period as compared with 9 pounds for the B35 group steers. In the combined 13-month period the A35 group steers made a total average gain of 435 pounds as com- pared with 348 pounds for the B35 group steers. Thus, the A35 group steers outgained the B35 group steers by an average 115 pounds in the supplement period; and while the B35 group steers outgained the A35 group steers by 28 pounds in the subsequent grazing pe- riod, the A35 group steers still had an 87-pound advantage in total average gain. FINISHING YEARLING AND TWO-YEAR-OLD CATTLE Studies in finishing cattle upon the range involved all the calf crops from 1935 through 1945 with the exception of those produced in 1943. The object of these experiments was to ascertain the possibilities of finishing cattle upon this type of range with the animals harvest- ing their own roughage while being full- fed concentrates. At the start of the fin- ishing period the animals were moved to smaller previously ungrazed pastures, such as 7E and 7W (fig. 2), when the forage upon the hill slopes was begin- ning to dry. Two-Year-Old Steers These experiments involved only two groups (A35 and A38) receiving con- centrates for finishing. The unsupple- mented groups (B35, B36, B37, and B38) were not finished for slaughter, and were sold as feeders except for the B35 group, which was killed to collect data on their condition and carcass ap- pearance. The data are presented in table 8. Management of these steer groups from weaning through their second graz- ing period has been presented in the pre- ceding section, "Feeding and Manage- ment of Calves after Weaning." Carrying steers upon the range until they were long 2 years of age entailed the feeding of the supplemented groups through a second supplement period. Supplementing was at the usual rate needed to promote daily gains of % to % pound in weaner calves. As shown by a comparison of the data in tables 4 and 8, the A35 steers were actually fed at a higher rate than the A36 calves but only made 0.22 pound daily gain, as compared with 0.58 pound for the weaner animals. The A38 steers were fed at the same rate as the A39 calves, and their daily gain was 0.11 pound, as compared with about 0.41 pound for the calves. The marked difference in average daily gains of the long yearling steers as compared with the weaner calves is explained by the fact the older animals had passed the age at which they had the greatest stimulation for skeletal and muscular growth and, consequently, did not make as efficient use of their supple- ments as did the younger animals, which were in this growth phase (Guil- bert, Hart, et al, 1944). The supple- ment periods of the A35 and A38 steers were about a month shorter than those of the A36 and A39 calves, because it is the practice to start supplementing weaner calves immediately after wean- ing, whereas the supplement periods of the older animals were delayed until [38] Table 8. Two- Year-Old Steers, Supplemented and Unsupplemented: Gains and Marketing Data Gains during supplement, grazing, and finishing periods Period and group Average weaning age, days Length period, days Supplements fed per head, pounds During period Total after weaning Average weight, pounds At weaning At end of period Average gain or loss, pounds For period Daily Supplement period I A35, 14 steers .... B35, 14 steers B36, 12 steers B37, 14 steers A38, 15 steers .... B38, 16 steers .... Grazing period I A35, 14 steers .... B35, 14 steers .... B36, 12 steers .... B37, 14 steers .... A38, 15 steers .... B38, 16 steers .... Supplement period II A35, 14 steers .... B35, 14 steers .... B36, 12 steers .... B37, 14 steers .... A38, 15 steers. . . . B38, 16 steers .... Grazing period II A35, 14 steers .... B35, 14 steers .... B36, 12 steers. . . . B37, 14 steers .... A38, 15 steers .... B38, 16 steers Finishing period A35, 14 steers .... A38, 15 steers .... 222 223 178 253 245 224 182 182 243 205 225 225 218 218 152 187 175 175 215 215 174 188 176 176 84 133 130 120 111 167 311 48 286 746 360 404 670 1,461 1,316 455 438 396 411 519 423 579 447 344 397* 626* 450* 890 785 664 652* 909* 778* 937 590 662 681* 939* 660* 1,130 999 905 979 1,133* 1,083 1,208 1,283 +124 + 9 — 52 - 14 +107 + 27 +311 +338 +320 +255 +283 +328 + 47 —195 — 2 + 29 + 30 —118 +193 +409 +243 +298 +194 +423 + 78 +150 +0.68 +0.05 —0.21 —0.06 +0.47 +0.12 +1.43 +1.55 +2.10 +1.36 +1.62 +1.87 +0.22 —0.91 —0.01 +0.15 +0.11 -0.67 +2.30 +3.07 +1.87 +2.48 +1.75 +2.61 +1.59 +2.00 Marketing data Group and disposal Average weight, pounds Average shrink- age in shipping, per cent Average dressing percent- age Selling price per cwt. Carcass grades, O.P.A.f Shipping Selling Carcass A35, slaughter 1,208 999 905 979 1,283 1,083 1,141 910 853 938 1,184 1,009 667 474 706 5.55 8.91 5.75 4.12 7.72 6.83 58.5 52.1 59.6 $ 8.75 7.50 7.40 8.75 10.50 8.45 1 AA, 13 A B35, slaughter 7B, 7C B36, feeder B37, feeder A38, slaughter 15 A B38, feeder * Weijhed after all-night shrink in a dry lot. t AA, Choice; A, Good; B, Medium; C, Common. [39] gains upon pasture alone had about ceased. Data presented in figure 4 and table 4 show that feed conditions during the supplement periods of the 1937-38 and 1940-41 seasons were more adverse than most such periods. This is further shown by the 195- and 118-pound average weight losses for the B35 and B38 steer groups, respectively, during their second supplement periods, as compared with a 2-pound loss for the B36 steers and a 29-pound gain for the B37 steers in their respective second supplement peri- ods (table 8). Thus the A35 steers, which had gained an average of 88 pounds more than the B35 steers by the end of the first grazing period, had increased this difference to 330 pounds by the end of the second sup- plement period, during which they had received an average of 746 pounds of supplements per head. Similarly the A38 steers, which had gained 35 pounds more by the end of the first grazing season, increased the difference in gain to 183 pounds by the end of the second supplement period, during which an average of 360 pounds of supplements per head had been fed the A38 steers. The second grazing period again found the thin-fleshed unsupplemented groups outgaining their heavier-fleshed supplemented mates. In a 133-day period the B35 steers made an average daily gain of 3.07 pounds and in a 167-day period the B38 steers made a 2.61 -pound aver- age gain. The A35 steers were allowed to subsist upon range alone for 85 days of a second grazing period, during which time they made 2.30 pounds average gain. In a similar 111-day period the A38 group steers made 1.75 pounds average gain. Towards the close of their second grazing periods, when the forage on the slopes was drying, the A35 and A38 groups were moved to smaller ungrazed pastures to be fed concentrates for finishing. Concentrates consisted of 43 per cent cottonseed cake and rolled bar- ley; however, at first a small portion of rolled barley was replaced with beet pulp to increase the palatability of the ration. The daily ration (once a day feeding) was increased as fast as prac- tical until 1 pound of concentrate mix- ture per 100 pounds live weight was being fed. Cottonseed cake also added palatability to the ration and at full feed comprised from 10 to 15 per cent of the concentrate mixture. At this feed- ing rate close observation was required in hot weather to detect steers starting to go off feed. When this occurred the daily ration was cut about a third and then returned gradually to full feed. Later, morning feedings were discon- tinued in favor of evening feedings, as it was thought that the extra heat pro- duced by the ingestion of the concen- trates would be more easily eliminated during the cool of the night. Data in table 8 show the A35 group required an average 404 pounds of con- centrates per head over a 48-day finish- ing period as compared with 670 pounds of concentrates for a 75-day finishing period for the A38 group. The A35 group had an average selling weight of 1,141 pounds and a dressing percentage of 58.5, as compared with a 1,184-pound average selling weight and 59.6 dressing percentage for the A38 group. Only one animal in the A35 group had sufficient covering to grade Choice. All the other steers of both groups finished in the Good grade and the fat was only slightly yellow. There were objections to the heavy carcass weights, and at the time lighter-weight carcasses comparable in grade to the A38 group sold from $1.00 to $1.50 per hundredweight higher. The B35 group were sold for slaughter at the same time as the A35 group. While they were definitely of the feeder grade, it was desired to secure some slaughter data of this class of animal. Their 910-pound average selling weight was 231 pounds below that of the A35 [40] group and their dressing percentage was only 51.1. The carcasses graded Low, Medium, and Common and were unsatisfactory in that they had practic- ally no fat covering while some were dark-cutting and chilled with an off color. In none of the 4 years' data given in table 8 did the unsupplemented groups attain sufficient finish for desirable slaughter animals. The data do show however, that by the use of supplements it is possible to finish 2-year-old steers to a Good grade upon this type of range. Yearlings Previously Supplemented for Vi to 2 3 Pound Daily Gain Six groups of animals (A36, A37, A39, and B39 steers, and A37 and A38 heifers) were involved in these experi- ments. The data are given in table 9. All but the B39 steers were finished and the finishing procedure used was the same as previously reported for the finishing of 2-year-old steers except that fishmeal and molasses were the concen- trates used in finishing the two A37 groups. The data show marked variations in length of finishing periods for the year- ling steer groups, as well as in selling weights, dressing percentages, and car- cass grades. In each case the finishing period was terminated before the steers had reached the desired degree of finish because the range roughage had com- pletely dried and daily weight gains no longer warranted the heavy feeding. While the A36 group steers were weaned just before the adverse wet winter period of the 1937-38 season, they received adequate supplements to promote average daily weight gains of 0.60 pound for the supplement period. The supplement period did not end until early March, and the new forage growth after that date was so good that the steers made average daily gains of 2.42 pounds in the subsequent grazing period. Then after a 70-day finishing period they sold at the low average weight of 879 pounds. Dressing percent- age was 57.0, and the average carcass grade for the group was Good. The A39 steers, which were similarly supplemented and then finished with cottonseed cake and rolled barley, also had a poorer than average supplement period the 1940-41 season. They did not receive adequate supplements for the usual gain, and their average daily gain for the period was only 0.44 pound. In the following 104-day grazing period their average total weight gain of 166 pounds was markedly below the 203- pound average gain of the A36 group steers for their 70-day grazing period. The finishing period extended over a 104-day period in an attempt to reach the desired degree of finish, but without success. Their average selling weight was 927 pounds with a dressing percent- age of 56.2, and the carcasses graded from high Medium to low Good. Total concentrates fed after weaning were an average 1,124 pounds per head with a total average weight gain for the period of 410 pounds, as compared with a total of 1,146 pounds of supplements per A36 steer and a total average weight gain of 414 pounds. The B39 steers, which subsisted upon grass the entire time after weaning, made total average gains of only 251 pounds. Fishmeal and Molasses as Supplements As previously stated, the A37 weaners were supplemented with fishmeal and molasses (table 4) the supplement period after their weaning. The average 0.75 pound daily gain of the A37 steers for this period was greater than that of the A36 and A39 groups of steers for their respective supplement periods. While self-feeding the supplements to the A37 group during their supplement period did not prove practical, the A37 steers were self-fed an average 127 pounds of molasses per head over the following [41] Table 9. Yearling Steers and Heifers Supplemented for !4 to Vz Pound Daily Gains as Weaners: Gains and Marketing Data One group of unsupplemented steers included for comparison Gains during supplement, grazing, and finishing periods Average weaning age, days Length period, days Supplements fed per head, pounds Average weight, pounds Average gain or loss, pounds Period and group During period Total after weaning At weaning At end of period For period Daily Supplement period A36, 11 steers A37, 8 steers 218 246 233 242 253 248 243 205 204 204 205 225 84 102 104 161 102 71 70 89 104 48 60 598 626* 399 626* 286 127J 154$ 548 951* 725 403* 313 1,146 1,704* 1,124 1,183 599 465 497 517 467 470 455 610 651 607 f 425 f 583 573 813 842 773 f 781 751 703 929 934 979 810 848 +145 +154 + 90 — 42 +113 +118 +203 +191 +166 +356 +168 +130 +116 + 92 +206 + 59 +145 +0.60 +0.75 +0.44 -0.21 +0.55 +0.52 +2.42 +1.87 +1.60 +2.21 +1.65 A39, 18 steers B39, 11 steers A37, 7 heifers A38, 10 heifers Grazing period A36, 11 steers A37, 8 steers A39, 18 steers B39, 11 steers A37, 7 heifers A38, 10 heifers Finishing period A36, 11 steers A37, 8 steers +1.83 +1.66 +1.03 +1.98 +1.23 A39, 18 steers A37, 7 heifers A38, 10 heifers +2.42 Marketing data Group and disposal Average weight, pounds Average shrink- age in shipping, per cent Average dressing percent- age Selling price per cwt. Carcass grades, O.P.A.§ Shipping Selling Carcass Steers A36, slaughter A37, slaughter A39, slaughter B39, feeders Heifers A37, slaughter A38, slaughter 929 934 979 781 810 848 879 888 927 718 758 796 501 480 521 419 444 5.38 4.92 5.31 8.06 6.42 6.13 57.0 55.2 56.2 55.3 55.8 $ 8.50 8.75 10.50 9.00 8.00 8.50 1 AA, 9 A, 1 B 8B 9 A, 9B 3 A, 3 B, 1 C 1 A, 9B * Fishmeal and molasses. f Weighed after all-night shrink in dry lot. X Molasses self-fed. § AA, Choice; A, Good; B, Medium; C, Common. 102-day grazing period. Their average steers. They were then hand-fed fishmeal daily gain of 1.87 pounds for the period was a little better than that of the A39 group steers for their grazing period but markedly below that of the A36 daily (2 pounds per head maximum) and self-fed molasses over a 89-day finishing period. Their average daily gain of 1.03 pounds for the period was [42] markedly below the respective gains of the A36 and A39 steers. Average selling weight was 888 pounds with a dressing percentage of 53.2, and all carcasses were in the Medium grade. All three steer groups fed for finishing were considered, by the buyers, to be lacking in sufficient finish for slaughter, and the consensus was that they should have been placed in a feedlot for further feeding before slaughtering. Two groups of heifers, A37 and A38, not desired for replacements, were also finished. They were fed in the same manner as the steer groups, with the A37 heifers being fed fishmeal and molasses and the A38 heifers cottonseed cake and rolled barley (table 9). While heifers are easier to fatten at the yearling age than steers, neither of these groups were finished past the Medium grades and had low yields of 55 per cent. Yearlings Previously Supplemented for 1 to 1 ! 4 Pounds Daily Gains Since previous experiments at finish- ing long-yearling steers had not given satisfactory results, new experiments were designed to study the finishing of yearling steers that had been supple- mented for daily gains of 1 to l 1 /^ pounds during the supplement period after weaning, failure in the previous experiments being attributed to the fact the steers had not attained sufficient fleshing before the beginning of the finishing period. In experiments prior to this time (1940 calf crops) the groups being supplement-fed, and then finished for slaughter, were produced by the A herd while the unsupplemented groups were produced by the B herd. In order to have more steers available in future finishing experiments, the steers pro- duced by the B herd were combined with those of the A herd at weaning. The poorer animals of the former group were discarded where possible to de- crease variation within the groups. The first experiment along these lines has already been reported (Guilbert, Hart, et al., 1944). The results are sum- marized in table 10 (data for A40/1 and A40/2 groups). After eliminating the five poorest ani- mals, the remainder of the 1940 steers (A40 group), were supplemented in the manner previously described for daily weight gains of % to % pound and then finished in the same way as for the 2-year-old steers. As shown by table 10, their average selling weight of 957 pounds, 58.0 per cent yield, and carcass grades in the Medium to Good grades are comparable to the previous groups finished in a like manner (table 9). Beginning with the 1941 calf crop, a series of experiments was conducted in which a group of steers were finished after being supplemented for average 1 to 1%-pounds daily gains as compared with a group fed for the !/2 to % pound average daily gain. Furthermore, all groups finished were fed concentrates twice daily during the finishing period with 1.5 pounds of feed fed per hundred pounds live weight when on full feed. Even though half again as much con- centrates were fed daily as in the pre- vious finishing studies, less trouble was encountered with the steers going off feed. The weaner steers of the 1941 calf crop were divided into two groups of 14 each and one group of 15. These groups were designated as A41/1, A41/2, and A41/3, respectively. One of the A41/2 steers died from a rattlesnake bite before the experiment was com- pleted. During the supplement period after weaning the A41/1 and A41/2 groups were pastured together and sup- plemented in the usual manner with cottonseed cake and rolled barley to produce average daily gains of % to % pound daily while the A41/3 group was fed at a heavier rate to produce average daily gains of 1 to l 1 /^ pounds. Because of the heavier fleshing of the heavier-fed steers it was necessary to [43 Table 10. Effect of Early and Late Supplement Feeding on the Gains and Market Value of Yearlings* Gains during supplement, grazing, and finishing periods Average weaning age, days Length period, days Supplements fed per head, pounds Average weight, pounds Average gain or loss, pounds Period and group During period Total after weaning At weaning At end of period For period Daily Supplement period A40, 12 steers A40/1, 8 steers A40/2, 8 steers Grazing period A40, 12 steers A40/1, 8 steers .... A40/2, 8 steers Finishing period A40, 12 steers A40/1, 8 steers A40/2, 8 steers 246 237 232 239 183 183 84 164 164 118 94 94 489 717 590 937 1,021 1,078 1,426 1,738 1,668 527 483 481 667 f 678 461 761 1 906 787 1,042 1,036 923 140 195 —20 94 228 326 281 130 136 0.59 1.07 -0.11 1.12 1.39 1.99 2.38 1.38 1.45 Disposal data (all groups marketed as slaughter cattle) Group Average weight, pounds Average shrink- age in shipping, per cent Average dressing percent- age Selling price per cwt. Carcass grades, O.P.A.f Shipping Selling Carcass A40, 12 steers 1,042 1,036 923 957 969 868 555 573 521 8.10 6.4 5.9 58.0 59.1 60.0 $13.34 13.88 13.48 7 A, 5B A40/1, 8 steers 5 A, 3B A40/2, 8 steers 4 A, 4B * Data on A40/1 and A40/2 are from the experiment reported by Guilbert, et al. (1944) , although not given there in this form. t Weighed after all-night shrink in a dry lot. t AA, Choice; A, Good; B, Medium; C, Common. extend their supplement period until the new forage growth was more advanced than would be required for thinner- fleshed animals, in order to prevent a regression in weight gains. A summa- tion of the data is given in table 11. These data show the A41/1 and A41/2 steers were each fed a total of 505 pounds of supplements over a 235-day period and made average daily gains of 0.49 and 0.58 pound respectively. The A41/3 steers were each fed a total of 939 pounds of supplements over a 250-day period and made average daily gains of 1.00 pound. The supplement period of the 1942-43 season was more adverse than usual and gains the following grazing period were below average. In the grazing period the A41/2 and A41/3 groups were moved to the usual small ungrazed fields as the forage began to dry and were fed for finishing. After a 64-day finishing period the A41/3 group sold at an average weight of 931 pounds. They dressed 59.2 per cent with three of the carcasses grading Choice and the remainder Good. Because of their thinner condition it was necessary to feed the A41/2 group over a 98-day period, and they sold at an average weight of 894 pounds. Their dressing percentage was 58.9 with four carcasses [44] Table 11. Yearling Steers Supplemented for 1 Pound and for Vi to Va Pound Daily Gain as Weaners: Gains and Marketing Data Gains during supplement, grazing, and finishing periods Period and group Average weaning age, days Length period, days Supplements fed per head, pounds During period Total after weaning Average weight, pounds At weaning At end of period Average gain, pounds For period Daily Supplement period A41/1, 14 steers A41/2, 13 steers A41/3, 15 steers A44/1, 13 steers A44/2, 13 steers A44/3, 13 steers A45/1, 12 steers A45/2, 11 steers A45/3, 12 steers Grazing period A41/1, 14 steers A41/2, 13 steers A41/3, 15 steers A44/1, 13 steers A44/2, 13 steers A44/3, 13 steers A45/1, 12 steers A45/2, 11 steers A45/3, 12 steers Finishing period A41/2, 13 steers A41/3, 15 steers A44/2, 13 steers A44/3, 13 steers A45/1, 12 steers A45/3, 12 steers 224 234 226 238 240 240 208 226 213 235 235 250 183 183 232 195 230 230 131 72 57 132 103 54 92 111 57 64 87 55 110 82 505 505 939 314 314 815 735 1 814 814 1,133 719 785 541 1,080 804 449 445 450 472 472 472 436 435 436 505 314 814 1,638 1,658 1,099 1,356 1,815 1 1,618 565* 581* 699* 568* 581* 715* 583* 671* 682* 823 718* 808* 785 727* 799* 734* 827 807* 971 993 915 924 957 979 116 136 249 96 109 245 147 236 246 258 137 109 217 146 84 151 156 125 253 185 188 125 223 172 0.49 0.58 1.00 0.52 0.59 1.06 0.75 1.03 1.07 1.97 1.90 1.91 1.64 1.41 1.55 1.64 1.40 2.19 2.58 2.89 2.16 2.27 2.03 2.10 Marketing data Group and disposal Average weight, pounds Average shrink- age in shipping, per cent Average dressing percent- age Selling price per cwt. Carcass grades, O.P.A4 Shipping Selling Carcass A41/1, feeders . . . 823 971 993 785 915 924 957 827 979 783 894 931 741 852 891 893 799 935 516 551 518 519 518 533 4.86 7.92 6.24 5.60 6.88 3.57 6.60 3.38 7.34 58.9 59.2 60.7 58.2 58.1 57.0 $13.18 14.00 15.00 14.70 18.83 16.51 24.50 21.51 24.50 A41/2, slaughter A41/3, slaughter A44/1, feeders 4 AA, 8 A, 1 B 2 AA, 13 A A44/2, slaughter A44/3, slaughter A45/1, slaughter A45/2, feeders 13 A 13 A 12 A A45/3, slaughter 10 A, 2 B * Weighed after all-night shrink in dry lot. f 366 pounds of total was wheat straw mixed with molasses. j AA, Choice; A, Good; B, Medium; C, Common. [45] grading Choice, eight Good, and one Medium. As shown by table 11, there was not much difference in total amounts of feed fed or dressing percentage of the A41/2 and A41/3 steers, but the latter had a 37-pound advantage at sell- ing and sold at $1.00 per hundred- weight more than the former group. The A41/1 group remained on natural forage until it dried, when they were sold as feeders at an average selling weight of 783 pounds. Sufficient steers to form three experi- mental groups were not available in the 1942 calf crop, and the weaning weights of the 1943 calf crop were so low be- cause of the adverse 1943-44 season that only a few weaner heifers were retained for breeding-herd replacements. The 1944 calf crop was divided in- to three groups (A44/1, A44/2, and A44/3) of 13 head each, with the groups receiving treatment comparable to the respective 1941 groups. Table 11 shows marked differences in results. Total rainfall for the 1945-46 season was only 13.87 inches and consequently the total forage produced was below average and also matured at an earlier date. The supplement period for the A44 groups was shorter than that required for the A41 groups, with 191 pounds less total supplements per head for the lighter-fed groups and 124 pounds less for the heavier-fed group. Average daily gains of the A44 groups were quite similar to those of the respective A41 groups. The 1946 grazing period was about the same length as in the 1943 season except for the A44/2 group steers, which were maintained upon pasture about 30 days longer than the A41/2 group steers (table 11 ) . Average daily gains of 1.41 to 1.64 pounds of the A44 groups, for the period, were markedly below the 1.90 to 1.97 pounds average daily gain of the A41 groups. Shortly after mid-April the forage began drying rapidly, and feed- ing of the A44/2 and A44/3 groups for finishing was started. The steers were fed cottonseed cake and rolled barley in the previously described twice-a-day feeding. Because of drought conditions it was decided to try and finish them to the O.P.A. A grade. Thus, the heavier- fleshed A44/3 group was fed for a 55- day finishing period while the A44/2 group required an 87-day finishing period to reach the same degree of finish. The A44/3 steers' average selling weight was 891 pounds, dressing percentage 58.2, and all carcasses graded A, as com- pared with an 852-pound average sell- ing weight, 60.7 per cent yield and all grade A carcasses for the A44/2 group. In this experiment the low-fed A44/2 steers received 255 pounds less total feed per head than the A44/3 steers, but had a higher yield and ended with carcass weight almost identical. The A44/1 group were sold as feeders at the close of the grazing period with a selling weight of 741 pounds. The steers of the 1945 calf crop were also divided into three groups after weaning (table 11). In contrast with the previous studies, only the A45/1 group was fed for moderate gains while the A45/2 and A45/3 groups were fed for the higher rate of gain during the sup- plement period after weaning. The sup- plement period of the 1946-47 season was similar to that of the previous year and the gain and supplements fed the A45/2 and A45/3 groups were quite similar to those of the A44/3 group. The A45/1 group were also used as con- trols in another experiment during the dry-forage period after weaning. During this period they were fed 3 pounds per head daily of wheat straw that had been sprayed with molasses, in addition to cottonseed cake. Since their feeding rate was higher than the previous mod- erately fed groups, their average daily gain of 0.75 pound is also above the daily gains attained by the other mod- erately fed groups (except for the A37 steer group — table 9). [46] Drought conditions again prevailed the 1947 grazing period with below- average forage production and earlier than usual drying of the forage. As in the previous study, one moderately fed group (A45/1) and one heavily fed group (A45/3) were to be finished for slaughter. The 92-day grazing period for the A45/1 group was between that of the A41/2 and A44/2 groups, and their 1.64-pound average daily gain was below that of the A41/2 group and greater than the A44/2 group. The 57- day grazing period of the A45/3 group was similar to those of the A41/3 and A44/3 groups while their 2.19-pound average daily gain was greater than the two previous corresponding groups. Both the A45/1 and A45/3 groups were moved to finishing pastures before the close of the grazing period and twice-a-day feeding for finishing initi- ated. Drought conditions for this period in 1947 were more severe than in the previous year and longer periods were needed to finish the steers to the O.P.A. A grade. After an 82-day finishing period the A45/3 group sold at an average weight of 935 pounds, had a dressing percentage of 57.0 with ten carcasses grading A and two B. The lighter-sup- plemented A45/1 group were fed over a 110-day period, sold at an average 893-pound weight, had a 58.1 per cent yield, and all carcasses graded A. There was little difference in total amounts of concentrates fed per steer (each A45/1 steer also received 186 pounds wheat straw and molasses mixture during the dry-forage period after weaning), but the A45/3 steers had an average 42- pound advantage in selling weight and an average 15-pound advantage in car- cass weight. The A45/2 group, which had been supplemented to promote an average 1.03-pound daily gain during the sup- plement period, were sold as feeders with an average selling weight of 799 pounds after a 111-day grazing period. After weaning, the steers of the 1946 calf crop were divided into three groups with the intention of replicating the study with the A45 steers. Drought con- ditions continued with resulting poor forage conditions that were unfavorable for finishing steers under the procedure being used. As a consequence this series of finishing studies was discontinued. The difficulties of attempting to pro- duce finished yearling cattle upon this range under the prevailing conditions are clearly indicated. While these results show that yearling cattle may be satis- factorily finished if the forage conditions are favorable, the climatic hazards are such that the area appears better suited for the production of feeder cattle. FEEDER-CATTLE PRODUCTION: RECOMMENDATIONS In their study of ranch management practices, in the "granite area" sur- rounding this station, Voorhies, et al. (1942) found that about half the ranch- ers ran steers which were sold off the grass at 2 years of age or older. The others ran cow and calf outfits and sold weaners or had no definite yearly mar- keting plan. Most of the steers from the area, because of the low quality of the forage, were sold as feeders. At this time a considerable proportion of the beef cattle marketed in California were 2 to 4 years of age and had been fattened upon grass or hay. As previously stated, however, the market demand had become more discriminatory with a greater de- mand for younger and lighter-weight animals with a high degree of finish. Thus range areas were becoming more important for the maintenance of breed- ing herds and grazing of stocker cattle to produce feeders than for the produc- tion of "grass fat" cattle. [47] Many factors must be considered to determine the best means of marketing the ranch feed supply. Production costs in relation to the selling price of calves, yearlings, and 2-year-olds, and total ton- nage of beef produced must be con- sidered for each ranch. Selling weights of the various age classes of feeder cat- tle, as affected by climatic and mana- gerial factors, are also of great im- portance in determining a marketing program. Some data on these latter fac- tors have been collected. Data on repro- duction and growth of young animals with and without supplements, as well as improvement in quality by the use of good bulls, have been presented and discussed in previous sections. Weaner Calves Many ranchers favor a cow and calf enterprise because they are not inclined to carry young growing animals, other than needed replacements, through the costly winter period. Furthermore, this type of setup is favorable to flexibility in management procedure, especially if early calving and weaning around July is practiced. There are times, in areas of mild winters, when favorable climatic conditions produce a surplus of forage and the weaners could be held upon the ranch a few months longer to utilize forage that might otherwise be wasted. Data in table 1 show that the supple- mented A herd produced weaner calves with an average weight of 464 pounds as compared to an average of 406 pounds for the unsupplemented B herd. (The production of the supplemented C herd will not be considered in this discussion because of influence of unknown factors. These are not to be ignored, however, for a rancher confronted with such a problem has cause for concern and need of a management procedure to overcome the difficulties.) The 58-pound difference in A and B herd average weaning weights is of considerable importance because weight and degree of fleshing are important factors in determining the suitability of weaners as feeders to be placed directly in the feedlot. These data also include the heifer calves, from which the best are usually selected for replacement purposes. Table 12. Average Weaning Weights and Ages of Steers Produced by the A and B Herds Herd A Herd B Calf crop Average weaning weight Average weaning age Average weaning weight Average weaning age 1935 441 465 497 519 507 517 470 445 412 501 473 435 492 479 221 218 246 245 231 239 231 236 248 256 241 220 247 240 409 411 423 467 445 432 402 363 415 404 362 393 412 1936 182 1937 253 1938 224 1939 242 1940 222 1941 235 1942 221 1943 244 1944 219 1945 205 1946 210 1947 230 1937-1947 Average 228 [48] The average figures presented in table 1 do not show the variations in annual weaning weights and such information is highly important in developing a marketing procedure. Presented in table 12 are the average annual weaning weights and ages for the steers produced by the A and B herds. These data, be- sides showing the previously discussed differences in the A and B herd total average weaning weights, show marked variations in annual weaning weights and ages resulting from variations in annual forage conditions. Besides the direct influence of variable forage con- ditions upon calf gains, there is the in- direct influence resulting from time and rate of breeding the cows. Thus, if feed conditions are favorable and the cows are bred rapidly at the start of the breeding season the calves will be older than those from cows slow to settle. It is to be noted that variations in annual weaning weights were as much as 100 pounds and occurred in the A herd as well as in the B herd. While the weaner steers from the A herd were heavier and more uniform, it is obvious that some calf crops, such as 1942, 1943, and 1946, did not carry sufficient fleshing for suit- able feeders. The use of calf creeps in the below-normal forage years to bolster weaning weights has been suggested, but it was not possible to use them in this study. It is doubtful if any of the B herd steer groups would have been con- sidered suitable as feeders. Not only were the animals thinner fleshed and of lighter weight, but the groups lacked uniformity. Yearlings More and more interest is being shown in the production of yearling feeder cattle. Several factors favor the production of this age of animal, as com- pared with marketing weaner calves, when a breeding herd is being main- tained. First, production studies have shown that a greater poundage of beef per acre may be produced. Secondly, a better opportunity for selecting replace- ment heifers exists because a better in- sight into the type cow the heifer will develop into is possible at the older age. Thirdly, on ranges of low carrying capacity, and marked annual fluctua- tions in forage production, in the more adverse years the calves may be sold as weaners and thus leave more acreage for the breeding herd. Fourth, a greater percentage of the total beef produced is from the cheaper range forage, and a shorter period of the more costly feed- lot feeding is required to finish the ani- mals for slaughter. Growth rates of weaner steers during the supplement period (with and with- out supplemental feed) after weaning and the subsequent grazing period, as well as variations in rate of gain due to fluctuations in forage conditions, have been previously discussed. Presented in figure 9 are the average growth curves for the steers produced in the calf crops from 1935 through 1939, the latter calf crop being the last in which B herd steers were carried past the weaning age. These data show that supplemented steers reached an average weight of 867 pounds, at 600 days in age, at the close of the grazing period, whereas the un- supplemented steers had an average weight of only 735 pounds, or 132 pounds less. Average amount of supple- ments fed per steer for the supplement period, not including the year fishmeal and molasses were fed, was 396 pounds. Evidence of variations that may occur in long-yearling steer weights at the close of the first grazing period is shown in tables 8, 9, and 11. These data show that the A35, A38, A41/1, and A44/1 group steers had average final weights of 890, 909, 823, and 785 pounds re- spectively. In comparison the average final weights of the B35, B36, B37, B38, and B39 group steers were 785, 664, 652, 778, and 781 pounds respectively. In all cases the supplemented groups [49] 1000 800 X CD bJ $ UJ iD < UJ > < Q O CL 600 400- 200 Heifers supplemented Heifers not supplemented ._. . Steers supplemented Steers not supplemented I I I I.I. J_L 60 120 180 240 300 360 420 480 540 600 AGE IN DAYS Fig. 9. Average growth curves for steers and heifers being supplemented as compared with similar groups not receiving supplemental feeds. were of greater uniformity and in good flesh so that they were well suited to go directly to the feedlot. The unsupple- mented groups were less uniform and at times (1936 and 1937 calf crops) so lacking in fleshing they were better suited as stocker cattle than feeders. The data discussed here, for the most part, were produced in years of above- average rainfall (fig. 4) and in the more favorable years it is possible that the final weights of some supplement- fed steers might be heavier (909 pounds for A38 group steers) than the weights desired by feedlot operators. On the other hand, in the more adverse years weaning weights will be down (412 pounds for the A43 group steers — table 12) and the long-yearling weights will be correspondingly light unless the sup- plemental feeding rate is increased to promote a faster rate of daily gain dur- ing the supplement period. This pro- cedure is well illustrated by the A45/2 steer data in table 11. This group of steers had a low weaning weight of 435 pounds, were supplemented for average daily gains of 1.03 pounds, weighed 827 pounds at the close of the following grazing period and had an actual selling weight of 799 pounds. Growth data of supplemented and un- [50] supplemented heifers (fig. 9) show average weights of 800 and 696 pounds, respectively, at 600 days of age. As pre- viously stated, the top animals of the A and B herd calf crops were selected for replacement purposes at weaning during this period of study. Treatment of those remaining after weaning was not consist- ent, hence information on long-yearling weights and condition cannot be given. Two groups of surplus heifers from the A herd were finished (table 9). Two-Year-Olds Only four groups of feeder steers were carried until they were over two years of age and all were unsupplemented groups. These were the B35, B36, B37, and B38 group steers. Their average shipping weights were 999, 905, 979, and 1,083 pounds respectively (table 8). In all cases their condition lacked suitable finish for slaughter, as illustrated by the slaughter data of the B35 group steers, but because of their age and fleshing only a short period in the feed- lot would be required for finishing. As with the other groups, their final weights would be variable in accordance with climatic conditions and in most cases their finished weights would be greater than the best market demands. HERD IMPROVEMENT THROUGH SELECTIVE BREEDING An essential of good animal-husbandry practice is improvement of the herd through culling and selection. This was an important part of this enterprise. Ex- cellent opportunity existed for record- ing information on heredity-environ- ment relations. Breeding Methods From January 1 until the herds were placed upon the "grazing intensity" pas- tures one bull was placed with herd A, one with herd B. These bulls, usually half brothers, were either proven or represented the best available from the standpoint of individuality and ancestry. They were alternated in succeeding years to diminish hereditary differences be- tween the two herds. Being with the cows early in the breeding season, these bulls sired most of the calf crops. When the cattle were placed in pastures 1 to 6 a bull was furnished for each pasture except during 1936, when only five bulls were available, and one had to be rotated between pastures 1 and 2. Measurements Taken Recording growth by various body meas- urements in addition to weight was initiated in 1942. Since variation in measurements as affected by environ- ment may help in understanding the selection problems encountered, the growth data are presented first. Mea- surement of width of hooks and of cannon bone were not started until 1944. All animals were measured when the calves were weaned. Measurements were taken with the animals standing as naturally as possible in a squeeze chute. At times difficulty was encountered, and considerable patience was required to secure normal posture. Culling of wild and nervous individuals, use of bulls with docile ancestry, and quiet handling in gentle cattle minimized the problem, and measurements were obtained with a degree of accuracy considered to be equal to those for the purebred herd at Davis. Head and cannon bone measure- ments were recorded to the nearest 0.25 centimeter; all others to the nearest centimeter. The measurement of the round extends from the point of the stifle (patella) on one side horizontally around the thighs to the point of the stifle on the opposite side. The round measurement is conditioned largely by muscle, and the ratio of round to height (^ X 100) may be considered a muscle: skeletal in- [51] dex and, therefore, an index of confor- mation (Gregory, 1933; Guilbert and Gregory, 1951). The D-W (dimension-weight index) (Yapp, 1924) is also an expression of conformation. It expresses the estimated volume of the animal (weight in pounds x an average value of 476 cc per pound) as a percentage of the volume in cubic centimeters of rectangular prism condi- tioned by height at withers squared times the length: / Weight X 476 v , m \ \ Height* X Length A 1UU y Body length is taken from the point of the shoulder horizontally to a line perpendicular with the pin bone, when the animal is standing squarely with forelegs at right angles with the top line. Culling and Selection of Replacements As has been brought out earlier, the intensity-of-grazing study required a definite number of cows in each pasture each season, which necessitated keeping a few extra animals as possible replace- ments of death losses. A few heifers were kept for this purpose the first few years of the experiment, and some of these were later used as replacements. Later extra animals were maintained for other experimental purposes and were avail- able as temporary fill-ins. All of the heifers from the first calf crop produced by the foundation heifers were divided between the A and B herds to increase their numbers. Except for the year culling was initiated (1938), the cows culled were removed from their respective breeding herds at the close of the grazing period. This date varied from the fore part of July to the fore part of August. Replacement animals for each herd were from their respective calf crops of the previous year that had been maintained through the supplement per- iod in a manner similar to that for their herd of origin. Actual culling and re- placement, therefore, was not initiated until the second calf crop (the first pro- duced by the newly established A and B herds) were long-yearlings. In the breeding and culling procedure the intent was to maintain hereditary equality between the two breeding herds. Lower percentage calf crops plus poorer development of the B herd heifer calves made this difficult: not only were there usually less heifers to choose from in the B herd calf crops, but also it was often impossible to distinguish genetic- ally inferior animals from those inferior because of improper growth and de- velopment. This was particularly true after such extremely severe winters as in the 1937-38 season or drought years as in the 1943-44 season. As a result, culling and replacement proceeded at a slower pace in the A herd than was pos- sible from replacements available, while undesired replacements were used at times in the B herd because no others were available. Criteria for the culling of cows were poor health, poor reproduction, poor conformation, wildness, and age. A sum- mation of the culling and reproduction data for the A and B herds is given in table 13. The procedure was the same for the C herd except that the founda- tion animals for this herd were mostly poorer-type cows culled from the A and B herds in 1941. Animals culled for poor health were those considered a poor risk to carry through another winter and reproduc- tive cycle and were sold while there was something of value to salvage. In culling for poor reproduction, barrenness, low milk production, deformed teats and ud- ders, and a tendency for prolapse were the main considerations. Since the study was concerned with factors causing abortions and stillbirths other than those produced by disease, cows were not usu- ally sold for these reasons. It is to be emphasized, however, that abortions and stillbirths are important reasons for cull- ing in commercial herds. Cows aborting 52] Table 13. Summation Culling and Replacement Data for A and B Herds Year and breeding herd Number cows dying Number cows culled Number replace- ments Number culled for: Poor repro- duction Poor type Poor health Wild- ness Age Other 2 2 4 2 1 3 1 1 1 1 1 7 12 10 6 9 4 6 7 8 10 6 1 8 8 5 5 3 6 7 1 9 7 71 55 15 16 9 8 9 4 8 7 7 7 8 8 8 8 5 5 4 5 5 3 12 7 90 78 3 4 16 10 31 26 3 1 3 2 13 10 * Refused to eat cottonseed cake. or dropping stillbirths frequently repeat such occurrences in later pregnancies and often apparently pass the trait on to their daughters (fig. 10). Cows failing to conceive in two consecutive years were considered barren and culled. Cows not producing sufficient milk to raise their calves were culled, as well as those with badly misshapen udders or with teats so enlarged at parturition that [53] 1938— H827 Cow sold 1944— Aborted 1945— S5 14 Cow culled 12 1935— HI 25 1 936— Aborted 1 937 — Died — premature 1938— H8 18 Cow culled 1941— HI 60 1942— S277 1943— S3 17 1944— Stillbirth 1945— H530 1948— Aborted 1946— S656 Cow culled Fig. 10. Summation calving data for foundation cow no. 12, her daughters and grand- daughters. All animals maintained in herds receiving supplements. Table 14. Weaner Calf Data from Two Cows Receiving Identical Treatment in the A Herd Cow no., calf crop, and calf no. Weaning age, days Weaning weight, pounds Weaning grade Cow 19 1935, calf H127 237 260 260 248 267 233 217 241 256 246 246 266 259 235 258 330 400 390 410 400 425 327 Good 1936, calf S220 Medium 1937, calf H703 Low Good 1938, calf S804 Low Good 1939, calf H957 Good 1940, calf H045 High Good 1941, cow dry 1942,* calf H280 Low Choice Total 2,682 465 530 560 545 585 600 511 481 Cow 45 1935, calf S104 Choice 1936, calf H225 High Good 1937, calf H709 Choice 1938, calf S809 High Good 1939, calf H959 Choice 1940, calf S041 Choice 1941, calf H124 Low Choice 1942,* calf S275 Low Choice Total 4,277 * Cows culled for age after weaning 1942 calf. [54 the new-born calf could not nurse with- out the cow's being first milked out. Ade- quate milk to supply the needs of the calf is of great importance in the ulti- mate weaning weight of the calf. This is well illustrated from two cows, nos. 19 and 45, which received identical treat- ment in the A herd (table 14). No. 19, graded low Choice, always had the ap- pearance of being a good "doer" be- cause she was usually in better flesh than the average of the herd. But it was noted that she was lacking in udder develop- ment and usually weaned a below-aver- age calf. The data show that the cow usually bred early in the breeding season. In comparison, no. 45, grading high Good, always looked rougher but had better udder development, and she consistently weaned calves above the average herd weaning weight. In a sum- mation of lifetime production no. 45's calves had a 152-pound greater average weaning weight, with a total of 1,595 pounds more weaner calf production. As previously stated, herd improve- ment through the use of better bulls and selection of heifers of best conformation for replacements was a part of the study. Thus, whenever possible, inferior-type cows were replaced by superior-type heifers. Attempts were made to maintain the same rate of culling poor-type cows in both the A and B herds, but this was difficult, as previously mentioned. For the 10-year period, 1938 to 1948, the percentages of heifers used for replace- ment were 47.4 and 57.7 for the A and B herds respectively. In herd A the proportion of first- or first- and second-generation females to original cows in different years was as follows: 1937, 15:31; 1938, 25:22; 1939, 30:15; 1940, 35:9; 1941, 35:10; and 1942, 36:8. The corresponding figures for herd B were, 1937, 14:30; 1938, 20:23; 1939, 23:22; 1940, 28:17; 1941, 34:9; and 1942, 38:7. Replace- ment was thus slower initially for herd B. After 1943 both breeding herds were made up exclusively of first-, second-, and third-generation replacements. Nervous or "wild" cows were con- sidered a detriment in the herd and cause for culling because they tended to excite other animals when the herds were being fed or worked. In the course of the study it was noted that the exceptionally nervous cow usually produced a nervous calf and that the weaner calves sired by a bull of nervous disposition were usu- ally more nervous than those sired by a bull with a quiet disposition. It must be mentioned, however, that ordinarily quiet-dispositioned cattle may be made wild by rough handling, and this is especially true with calves during the weaning process and immediately after. Supplemental feeding and quiet handling were found to be great aids in quieting a herd of cattle. In this study the cows were culled after reaching ten years of age. Varia- tions in weaner calf production of differ- ent-aged cows has been presented in a previous section. One herd A animal was culled because she refused to eat cottonseed cake. Effect of Plane of Nutrition A summary of data for the various measurements, at different ages, and comparison of herds A and B are given in table 15. Graphical presentation of weight, and selected measurements are shown in figure 11. In figure 11, data for selected measurements for herds A and B are contrasted and both are shown as percentages of the values attained by the parent herd at Davis. Important differences in growth and development given in table 15 and fur- ther illustrated in figure 11 are as fol- lows: Herd A exceeds B in average weight throughout life. This has already been demonstrated in the section, "Feeding and Management of the Breeding Herds," where seasonal weight varia- tions also are shown. [55] rH hn to Tj< CO CO t> m CO Tj« CO rr CO "«# w ^ CO "* oo oo oo oo 00 00 00 00 00 00 oo oo oo oo oo oo £*■►< rH O CO rH «tf CO "^ CO ^ CO "^ CO "^ CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO p-s X "*T , o in •*$ "^ CO CD CO CO tH CO CO "^ CO CO T-i CO o a. «s 00 00 00 00 oo oo oo oo 00 00 00 00 oo oo oo oo fig 5| 8 00 CO Ttf rH CO CO CO T* t- w t- co co co C~ CO rH 00 CO CO ^* ^ Tji Tji -* ^ ^ "^ ""^ «* Tji Tj" Tji tj* CO CO rH rH 00 o *• . a J3 in 3-« a CO rH CO i- tH CO CO <3i Tj< T-H ta co m co -^ CO t- 00 w m CO CO ^ ^ W ^ lO T}< m m lO lO m m m m CO CO £.S rH rH a g bo n d in" o t> tj* CO rH rH t> cd 00 t- co as 00 c^ CO 00 00 00 oq co 00 OS CO CO T-i T-i k 9 CO CO ■* ■<* ^ T^ ■>* ^ -tf X* *tf ^ -^ Tj* h-3 «- u CO Q 0) £ OS m t> o OS -* "* 00 co co 00 CO OS 00 rH r-j +3 00 o 4- £ l> C-" d d rH r^ CO rH CO* 1-1 ^t< 00 "* 00 t> rH t- OS c* 00 t- o CO -^ \m 00 t> OS 00 O C7J OJ OJ os os O OS OS OS OS OS *" CO CO 3 s ° rH i-H VI rH rH U) ti A s +» 0) ■g 9 3 0) o "0 rH «0 rj< t> lO rH C7S ■>* co oo ^ o "^ CO ■^ CO s OS CO rH C CO o O tJ< co m CO t- O CO OS O CO .5? CO Cs W tJ c» cc t- t- 00 t> 00 c- 00 c- 00 c~ .1 rH rH *S CD bo 5 M o oo O OS rH lf5 rH tH OS CO tH CO CO -^ CO ■^ CO ^ ^p as o ^ CO 0) a o <*§ J3 rH T- CO r- CO c< co c; CO c< CO c< CO ■w ® UO CO O CO t- "^ 00 cc OS t- O 00 o o O rH CO OS > <5 OS OS rH C CO r- CO c< CO Cs CO CO < ■•* • ,_ ■w" CO .ej-tJ bo C t- o CO w CO CO rH CO eo os O OS m c- CO OS in tm CO OS CO "<* tH 00 CO rH 00 CO CO OS O rH 00 o m co ' S § «* CO c- co O 00 O C5 o os rH OS rH o o q CO CO *z r-T tH~ i-T r-T rH~ rH~ rH rH S3 J2 .n e« CO CO "tf ■«* o ^ C7» iH t* rH O r- O "^ O0 00 SoS rH OS 00 CO 00 CO lf3 "tf ta ^ «^< ^ m ■** l> t- rH 1 I T3 J! ai ■d ^J d 4» S3 c IV ho « - o bi b, rj a S-l (H as as 00 o CO CO CO "^ »* CO 00 CO o 00 CO OS w rC *) CO 73 S<5 V 01 . w 45CO * ^SS *;> -0» *,Orl Ot- . <5 c S •g cS bo 2 00". 5? 1*1 o a> - Si O. C3 X WaW»iA%SM^vra^>^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^S ^:*ir?#t^»A : AW^iW^#JWrf^^ 4L>»^JjnfvttfiW^JI^^ W£Wtf^J£KI»»}JWMra#^ W.XU^AVrt+1** YWUfl HwttWY AWfWUW*WWU\ li tf AtfttW » ■ J tt ;t Wl/> i iY.i:<^a x v-v#w^ wa^;*™?**** '-«5»>^^v^ca»«biiv^ ^JW^nrei jxy**v CO • L7 vvtori ; SJZy*J6+S.7S?f*W.Ws?*afFJTf!,Firi*l\\&*V*XJ rtn^W-J *rttr^hv>^^XWA*>>^^^^i*^i^^ ^^^^^^^^^"^^^ ^-\^^^^^^ O t|oo ^ H W.XX. I *t, - f Ty«rt M« -«X»'JJ l-JArrt^?** -"» J i% V :***ttxXJt*i**rm«lV> \ w \ cvj li_ *^tt*w:^i&{i-iAjA4rmw*^^iw n AfrttK>>«AftK'J'* \tTJWM&¥*i M<* ¥ 1Z **Z?XJrt 10 oo CC 5 X z 9 s^^*^;r;vKWJ^*>^7^ffl&w?wtffT^^ ;+ '«***•<«■ a* «iw;.u if i vv j w:«h»/.^ //*^?r K*AiHir>; ittw.it* v? « k s S£ Z s ^■^ .. ^.vrnv^^^ ^£>^7^ ^r zzzzEzznzznss* ^ TT7P ■^ ^rwwem^ » fw.;.-j '^ratt^/>^*fi*^A»Xfrtf**>W^W»W W W ^ SY^»«gi^^»r^ fflgawgsy^^agZETOW ^>^^^> ^^.^>^.^>^>^.^.^.^>^^^"s"s ^ ^00 : ^?<^<&2ttr/ltt r RtiiuiI^X ftt&(ZV£AZU?*$?an& «/: *&*y^^V»n>^*£S5?W?^^ P CD CD X ■o c o N \ \ 1 CD UJ < o o O o o O O s o o <7> 00 h- CD if> > H H H H 2 B O M 00 H ^ M (O O co oo co o) 00 00 00 CD H *fj" +H- -H- ++ ila CO CO h; q Tt? tjJ ^ id te a jjaf ++ ++ -M- ^ ^ tJ< U5 LO lO CN lO o w w w to U) in to M OS q r-j t> CN 4b bo d oS a oc CO 00 CO 1> CO S 0) Hi «# ^t ^ -tf ^ ^ ^ ^i c e3 4) H— O Xj o oc CN cr CO Tj ■d CO 00 E o cr c T- oo OC CO H fr- t> t> C» "^ a. O) H rl , * > c O O H E s*a 1- rH tH 1- " rl T-T u «d 5 M xi *a C\l ■<* CO IC S o bo ■ ^ T3 03 *0 60 3 in a - a> .2? w d g > §s*s >> 2 .fc 0J ci © >H 3 2 § >> '0 S • « a> g ag s- s ■dg^og 0) 0) o M W ft W 5>IS loi^ «?TJ M fc * Nj ^« a; > m j- ^X! C bo ■?sl-?l ^ <» ai § ^.S d) £ Jo .2 3 d o *- -* C P vT &!| ■S 5 t X c CO S|? i s £ & "O U) o 5 _e « w .t < * 2 O hm c o "C 8 flL E o u J) X 8 V lO U3 O O 2 CO t- CO O o oo oo oo a * 5 c CO 00 t- o Ti< ^ ^ lO « jj •sj«! a tO tt N lO r O O lO o to to ^^ xj O H t- N 9 oo oo t> co 0) a Hi o T3 o W W Tjt r|< iH iH tH i-H hj a^g CN O "^ t> oo co t> co ffi bo iH tH iH iH *» X! «J fl CD 00 CO 00 r4 t4 t4 r4 r-i iH iH tH K^ . CN 00 CO CN C* C~ t- "^i 'S 3 O O O iH ^a rH t-I iH ® — ^-og CO CO iH O N CO rl ^ 5 Q c eS o d a> T3 M CD x> 43 C -ri a to " .3 > i 43 Eh A as 5.s «a .2 o ag 0)2 d o3 X! c8 "go ftd X! w i* J-S ■ga |n a-o *-• d T3 e3 XJ bp d * ft » 6-° d rt eSxl |g 43 d O e3 2 ® dimensional changes were associated with improvement in subjective evalua- tion by grading, from about low Good for the original cows to average Choice for second- and third-generation replace- ments. Greater uniformity, shorter and thicker cannon bone, and freedom from short, sloping rumps and other asym- metrical conformational characteristics were also obvious. Improvements in Grade and Weight of Calf Crop Data for grades and weights of the calf crops weaned for the ten-year period are shown in table 18. The data demon- strate the following points: 1. The average of the first three calf crops and the data in table 18 for 1937 and 1938 show that the first generation averaged about 82, or top Good. 2. After the cow herds consisted of selected first- and second-generation re- placements and the top of the original cows, no definite improvement trend was evident from the grades. 3. Average grade of calves from un- supplemented herd B cows generally was significantly lower than their herd A mates. Variation of grade with weaning weight is also apparent in year to year comparisons for both groups. Effort was made to minimize the effect of condition on grading, but restricted growth does more to change conformation than mere change in fatness, and complete allow- ance is practically impossible. 4. Under optimum conditions, the average grade of second- and third-gen- eration animals was close to 88, or aver- age Choice. This is doubtless somewhat higher than the average of purebred Herefords as a breed and approaches closely the average of the parent herd at Davis. According to unpublished data from the California Agricultural Experiment Station, there is little or no difference in percentage of wholesale cuts or propor- tion of lean, bone, and fat in equally fattened animals ranging from Good to Choice in grade. External measurement Table 18. Average Grade and Weight of Calf Crops at Time of Weaning, 1937-1947 Grade Weight, pounds Year born Heifers Steers Heifers Steers Herd A HerdB Herd A HerdB Herd A HerdB Herd A HerdB 1937 1938 1939 1940 1941 83.6 82.5 85.0 85.5 85.3 85.7 85.9 86.7 85.0 86.2 86.7 83.5 81.7 85.2 84.7 85.3 83.0 82.6 83.8 83.7 83.9 84.7 85.8 84.2 85.6 86.2 87.0 84.2 84.3 87.0 86.2 86.0 85.7 80.7 81.8 81.1 85.5 85.6 85.6 85.0 85.2 85.0 84.8 85.8 472 461 493 473 457 442 428 458 415 422 443 328 409 465 422 443 403 329 405 395 368 412 497 519 507 517 470 445 412 501 473 435 492 411 423 467 445 432 1942. . . . 402 1943 363 1944 415 1945 404 1946 1947 362 393 [64] differences likewise are not conspicuous. Even relatively long-legged Brahmans and half-bred Brahmans show little dif- ference from Herefords in these carcass characteristics although shape of rib and some other cuts are conspicuously dif- ferent in straight Brahmans of good beef quality. These data have focused atten- tion on higher yield at moderate finish and less feed per pound of gain as two variants that at any given price structure most affect value per pound and produc- tion cost of animals having acceptable carcass characteristics. It is probable that no improvement has been made in carcass yield although there are no critical data on this point. Improvements in Efficiency of Feed Usage During recent years, some of the bulls used have been subjected to feed-utiliza- tion tests after weaning. The bulls used that were sired by California Rover II have, on the average, required less than 700 pounds of feed, consisting of 65 per cent concentrates, for each 100 pounds of gain. The animals were each fed until they would correspond closely with top Choice to low Prime slaughter condition. Pattengale 3 ran feed-use tests on the steer progeny of three half brothers sired by California Rover II. Those from the San Joaquin Range cows required 691 pounds of feed per 100 pounds' gain, as compared with 797 and 775 respec- tively for first cross of similar bulls on plainer range cows in a cooperator's herd. Other tests have likewise con- tributed to the probability that efficiency of feed use has been increased. Accord- ing to data of Guilbert and Gregory (1952) , some of the factors contributing to higher grade are associated with or caused by ability to thrive. Thus high weight for age along with the high rate of maturity required to make higher grade is a good index of efficiency. 3 Pattengale, P. S. Unpublished data com- piled in 1950. MORTALITY AND MORBIDITY Accumulated knowledge of occurrence or prevalence of various causes of death or degrees of departure from normal health and well being is valuable in guiding corrective measures or research. During the 13-year period 1935 to 1947 inclusive, there were about 1,270 dif- ferent case reports recorded — not in- cluding the more obvious repetitions of unchanged conditions in individuals. The herd varied from 129 to 269 head in different years, with about a 226-head average. Breeding cows varied from 66 to 110 head; weaner calves from 43 to 78 head; the remainder consisted of varying numbers of yearling and 2-year- old steers and heifers. The approximate number of animal-years from which the 1,270 case reports have been made is 2,950. These figures are given to em- phasize the extremely large numbers of abnormalities that detract in small or large degree from optimum well-being and most efficient production. Attention to minor ailments is important, for col- lectively they exact an enormous toll. Death Losses in Breeding Cows The various categories of losses among breeding cows during the 13-year period were as follows, in terms of numbers of cow-years and percentages of total cow- years : Number Per cent Total cow-years 1,122 Parturition 8 0.71 Eversion of uterus 3 0.27 Uterine infection (herd B) . 3 0.27 Starvation (herd B) 2 0.18 Rattlesnake bite 2 0.18 Other causes 5 0.45 Total loss 23 2.05 [65] Calf Mortality in Utero and Prior to Weaning At the beginning of the study the foun- dation heifers purchased were found free from reactors to the agglutination test for infectious abortion, and no reactors have since been detected. A summation of all calf losses for the period 1935 through 1947 for the A, B, and C herds is presented in table 19. The losses of the foundation heifers in 1935 have been included with those of the A herd. These data show total calf losses, prior to weaning, of 9.4, 12.0, and 21.3 per cent for the A, B, and C herds, respec- tively. Of a total of 107 calves lost, 40 were due to stillbirths and 19 to abortions. These two sources account for 55 per cent of all the calves lost. Table 19 shows almost identical losses of 5.35 and 5.26 per cent of total pregnancies for the A and B herds, whereas it is 13.11 per cent for the C herd. Factors responsible for these losses are unknown, and the higher percentage of stillbirths in the C herd maintained in one pasture year round with supplemental feeding has already been discussed in the section, "Feeding and Management of the Breeding Herd." A shortage of vitamin A upon the area has not been substantiated, and lepto- spirosis, a recently discovered disease that may cause abortions and occurs over wide areas, is probably not involved in these cases. Calf losses caused by dystocia, death of dam, and by starvation were higher in the B herd, especially after drought years, long winters, or other adverse forage conditions. The two calves lost by starvation in the A herd were caused by one cow's having teats too large for the calf to nurse, and another cow's failure Table 19. Calf Losses and Retained Placentas in the Three Breeding Herds Total number of animals Percentage Item Herd A, 1935-47; supple- mented Herd B, 1936-47; no sup- plements Herd C, 1941-47; supple- mented Herd A Herd B HerdC Total pregnancies Total calves weaned 467 426* 342 302* 122 100 Calf losses : Abortions Stillbirths From dystocia 10 15 4 3 2 10 7 11 5 6 6 6 41 2 14 3 3 | 5.35 9.4 5.26 12.0 13.11 From dam's death From starvation From other causes Total 44 22 21.3 Retained placentas : Cows with retained placentas Cows kept after retained placentas. . . Cows rebreeding after retained pla- centas 80 62 46 97 68 38 29 20 16 17.1 74.2 28.4 55.9 23.8 80.0 Difference between total pregnancies and calves lost plus calves weaned is due to twins dropped. [66] to "make bag" at parturition. All starva- tion losses in the B herd were attributed to impoverished condition of the dams. Most of the calf losses from "other causes" were due to death from unknown causes a few weeks after birth. Four calves were killed by coyotes in 1935, and 35 coyotes were trapped on the area in 30 days. Regular fall trapping of coyotes was instigated, and no further losses from this source were encountered. Other known causes of death were rattle- snake bite, diarrhea, and pneumonia. Death Losses from Weaning to Three Years of Age Losses from weaning to 3 years of age were very low, amounting to only 10 animals out of 1,800, or 0.56 per cent. Rattlesnake bites accounted for 4 deaths, illness 4, and accidents 2. Retained Placentas and Their Effect on Rebreeding The data in table 19 show an incidence of 17.1, 28.4, and 23.8 per cent of re- tained placentas for the A, B, and C herds, respectively. Retained placentas were more prevalent in the B herd in the early favorable-forage years, but when forage conditions were droughty or quite adverse during the calving period, the incidence was equally present in all three herds. During such adverse periods sup- plementing with cottonseed cake and rolled barley did not alleviate the inci- dence of retained placentas. Supple- mented cows were, however, better able to ward off ill effects of possible uterine infections, whereas some B herd cows were lost from the combined effects of poverty and uterine infection. In the absence of specific infection, future re- production is not necessarily affected. One herd B cow had a calf each year for four successive years with a retained placenta each year. Animals with Sore Eyes Of the various causes of sore eyes, those responsible for inflammation of the eye- lids are probably of greatest importance (45.5 per cent of all sore eyes) because of their greater incidence and the possi- bility that they may lead to eye cancer. The lower eyelid is usually involved, with the afflicted areas just below the eyelash. The condition may be mani- fested by an irritated or sore spot, but most frequently by a wartlike growth that may extend out from the lower eye- lid as much as an inch. These are easily broken off, leaving an ulcerated area on the margin of the lid. Treatment by cutting out the growth and applying silver nitrate styptic has been successful, though the growths often recur. Fre- quently these growths become progres- sively worse and may suddenly become malignant. In this study cows with badly inflamed eyelids were culled and sold, only two being completely lost. Irritation of the haw, though of low incidence, may lead to eye cancer, but is easily treated by cutting out the haw while in early stages of inflammation. Grass awns, mostly from ripgut brome, were responsible for about 17 per cent of the total eye cases. The great- est incidence of this trouble is in summer after maturity of the forage. Pinkeye may, at times, cause consider- able trouble. During this 13-year period of study, cases of pinkeye were recorded in 1944, 1946, and 1947. The incidence was greater in mid- and late summer, with the newly weaned calves most af- flicted. Abscesses A total of 48 cases of abscesses were recorded during the study period. Most of the abscesses were about the head and throat and were considered to be mostly the results of penetrating grass awns followed by actinomycosis. These ab- [67] scesses frequently rupture in the oral cavity or exteriorly and thereby increase the distribution of the causative ray fungus on the feed, with resulting greater incidence. Fly Strike This is a general term used to denote maggot infestation of wounds. Open un- treated wounds in the summertime fre- quently become infested with blow-fly maggots, but the greatest difficulties are encountered when myiasis from the screw-worm strike is prevalent. Twenty- five out of the 34 cases occurred in 1940. Most of the screw-worm strikes occurred in the navels of newborn calves and under branding scabs. Treatment of calf navels and wounds with a fly repellent during the period when screw worms are active is effective in reducing the inci- dence of fly strike. Snake Bites Studies by Fitch (1949) have shown the experimental area to have a rattlesnake population of about 1 snake per acre. Forty known cases of animals bitten by rattlesnakes were recorded, and of these 7 died. The cattle are apparently most often bitten while grazing, since 32 of the recorded bites were about the head. Barring asphyxiation from mechanical closing of the respiratory tract or chance deposit of the venom directly into the blood stream, cattle will usually recover without treatment. In some cases an ab- scess later develops at the site of the bite. [68] LITERATURE CITED ASDELL, S. A. 1949. Nutrition and the treatment of sterility in dairy cattle; a review. Jour. Dairy Sci. 32: 60-70. Bentley, J. R., and M. W. Talbot 1945. How many head. Western Livestock Jour. 23 (43, July 15) : 21-24. 1951. Efficient use of annual plants on cattle ranges in the California foothills. U. S. Dept. Agr. Cir. 870: 1-51. DUREST, J. U. 1931. Der Rinderzucht. 759 pp. J. Springer, Berlin, Germany. Fitch, H. S. 1949. Study of snake populations in central California. Amer. Midland Nat. 41 (3) : 513-79. Glading, Ben, H. H. Biswell, and C. F. Smith 1940. Studies on the food of the California quail in 1937. Jour. Wildlife Mangt. 4: 128-44. Gordon, Aaron, and Arthur W. Sampson 1939. Composition of common California foothill plants as a factor in range management. California Agr. Exp. Sta. Bui. 627: 1-95. Gregory, P. W. 1933. The nature of size factors in domestic breeds of cattle. Genetics 18: 221-49. GUILBERT, H. R. 1942. Some endocrine relationships in nutritional reproductive failure ; a review. Jour. Anim. Sci. 1 : 2-13. Guilbert, H. R., and P. W. Gregory 1952. Some features of growth and development of Hereford cattle. Jour. Anim. Sci. 11: 3-16. Guilbert, H. R., and G. H. Hart 1946. California beef production. California Agr. Ext. Cir. 131: 1-157. Guilbert, H. R., G. H. Hart, K. A. Wagnon, and H. Goss 1944. The importance of continuous growth in beef cattle. California Agr. Exp. Sta. Bui. 688: 1-35. Guilbert, H. R., S. W. Mead, and H. C. Jackson 1931. The effect of leaching on the nutritive value of forage plants. Hilgardia 6: 13-36. Hammond, J. 1920. On the relative growth and development of various breeds and crosses of cattle. Jour. Agr. Sci. 10: 233. 1940. Farm animals, their breeding, growth and inheritance. 199 pp. Longmans, Green & Co., New York, N. Y Hart, G. H., and H. R. Guilbert 1928. Factors influencing percentage calf crop in range herds. California Agr. Exp. Sta. Bui. 458: 1-43. 1933. Vitamin A deficiency as related to reproduction in range cattle. California Agr. Exp. Sta. Bui. 560: 1-30. Hart, G. H., H. R. Guilbert, and H. Goss 1932. Seasonal changes in the chemical composition of range forage and their relation to nu- trition of animals. California Agr. Exp. Sta. Bui. 543: 1-62. Hart, G. H., H. R. Guilbert, K. A. Wagnon, and H. Goss 1947. "Acorn calves": a nonhereditary congenital deformity due to maternal nutritional de- ficiency. California Agr. Exp. Sta. Bui. 699: 1-24. Howell, C. E. 1927. Beef cattlf feeding trials, 1921-1924. California Agr. Exp. Sta. Bui. 421 : 1-12. Hutchison, C. B.( and E. I. Kotok 1942. The San Joaquin Experimental Range. California Agr. Exp. Sta. Bui. 663: 1-45.— Huxley, J. S. 1932. Problems of relative growth. 276 pp. Methuen & Co., London, England. [69] Jones, Burle J., and R. M. Love 1945. Improving California ranges. California Agr. Ext. Ser. Cir. 129: 1-48. Kidwell, J. F., P. W. Gregory, and H. R. Guilbert 1951. A genetic investigation of allometric growth in Hereford cattle. Genetics 37: 158-74. Knapp, B., Jr., A. L. Baker, J. R. Quesenberry, and R. T. Clark 1942. Growth and production factors in range cattle. Montana Agr. Exp. Sta. Bui. 400: 1-13. Knox, J. H., and M. Koger 1945. The effect of age on the weight and production of range cows. New Mexico Agr. Exp. Sta. Press Bui. 1004: 1-5. McMeekan, C. P. 1940-41. Growth and development in the pig with special reference to carcass quality characters. Jour. Agr. Sci. 30: 276-337; 31: 1-161. Phillips, R. W. 1939. Relation of diet to reproduction. In: Food and Life. U. S. Dept. Agr. Yearbook 1939: 476-91. Talbot, M. W., and H. H. Biswell 1942. The forage crop and its management, pp. 13-49 in: Hutchison and Kotok, 1942. Talbot, M. W., J. W. Nelson, and R. E. Storie 1942. The experimental area. pp. 7-12 in: Hutchison and Kotok, 1942. Thompson, D. W. 1917. On growth and form. 793 pp. Cambridge University Press, Cambridge, England. Vergis, J. B. 1939. Effect of nutrition on the carcass quality of Suffolk cross lambs. Suffolk Sheep Soc. Year- book (Ipswich, England.) (Original not seen; cited by Hammond, 1940.) Voorhies, E. C, L. A. Crawford, R. L. Adams, and G. A. Carpenter 1942. Ranch organization and management in the granite area. pp. 83-95 in: Hutchison and Kotok, 1942. Wagnon, Kenneth A., and H. H. Biswell 1943. Two types of broad-leaf erodium in California. Madrona 7: 118-25. Wagnon, K. A., H. R. Guilbert, and G. H. Hart 1942. Experimental herd management, pp. 50-82 in: Hutchison and Kotok, 1942. Wagnon, K. A., and G. H. Hart 1945. Durango root (Datisca glomerata) poisoning of range cattle. Jour. Amer. Vet. Med. Assoc. 57 (820) : 3-5. Wallace, L. R. 1948. The growth of lambs before and after birth in relation to the level of nutrition. Jour. Agr. Sci. 38: 90-153, 243-302, 367-401. Yapp, W. W. 1924. A dimension- weight index for cattle. Amer. Soc. Anim. Prod. 1923: 50. [70 TABLE OF CONTENTS Introduction, p. 4 Resume of climatic conditions and forage production, p. 6 General management practices, p. 12 Forage production as measured by livestock weight changes, p. 15 Supplemented versus unsupplemented range forage for the breeding herd, p. 18 Rotated versus yearlong pastures, p. 24 Grazing intensity, p. 25 Supplemented versus unsupplemented range forage for calves, p. 32 Finishing yearling and two-year-old cattle, p. 38 Feeder-cattle production: recommendations, p. 47 Herd improvement through selective breeding, p. 51 Mortality and morbidity, p. 65 Literature cited, p. 69 20m-l.'59(3233)MR AIM X FOR THE i BLUE RIBBON JOBS IN ANIMAL HUSBANDRY THE BEST POSITIONS go to the best prepared. And animal hus- bandry has many top-notch ca- reers for those who aim high, MANAGEMENT • SALES • OPERATIONS commercial ranches . . . purebred herds and flocks stockyards . • • feed companies . . . fairs • . . expositions RESEARCH ■ EDUCATION • EXTENSION 1m? The best preparation is a better education. Employers look on agricultural training at the University of Cali- fornia at Davis as a better educa- tion — standards required of enter- ing students are high . . . leaders in agricultural studies make up the faculty . . . facilities for studies and research are complete . . . the Uni- versity experimental farm is one of the nation's finest . . . the Col- lege of Letters and Science on the same campus broadens the scope of education. BLUE RIBBON FACILITIES LIVESTOCK . . . breeds of economic importance, for instruction in breeding, feeding, management, and judging. LABORATORIES . . . nutrition, physiology, genetics, wool; respiration chamber and psychrometric room for large animals; small-animal colonies. for further information see the College Entrance Advisor at your county Extension office or write University of California * Davis, California