>'K Division of Agricultural Sciences UNIVERSITY OF CALIFORNIA ^«&£ Reserve REPRODUCTION DIFFICULTIES IN RANGE BEEF CATTLE K. A. WAGNON F. D. CARROLL CALIFORNIA AGRICULTURAL EXPERIMENT STATION BULLETIN 822 Mortalities caused by reproduction difficulties result in heavy financial losses in the range cattle industry, and there- fore data are needed on the amount and cause of different types of such deaths. This publication summarizes data on reproductive losses gathered from 22 years of observation of several experimental cattle herds exposed to different management methods. The study suggests probable causes of some losses, describes factors that may be involved in others, and discusses some which are unexplained. FEBRUARY, 1966 THE AUTHORS: K. A. Wagnon is Specialist in the Experiment Station, Davis; F. D. Carroll is Professor of Animal Husbandry and Animal Husbandman in the Experiment Station, Davis. Reproduction Difficulties In Range Beef Cattle INTRODUCTION JTor years many California stockmen have had excessive calf losses from unknown causes. This report discusses calf losses observed while engaged in other range cattle management studies, but it is the authors' hope that data presented here will encourage stockmen to study their reproduction losses more closely in order to help solve some of the problems in- volved. During earlier studies of range cattle management at the U. S. Forest Service- maintained San Joaquin Experimental Range in Madera County, it was noted that a large percentage of calf losses were due to abortions and stillbirths not asso- ciated with dystocia (Wagnon, et ah, 1959). 2 The cows had not been tested for pregnancy and it is likely that some re- ported as "dry" had actually aborted. Very few aborted fetuses were found, but the majority of the stillbirths were; most of these appeared normal and apparently were dropped at term. A few were small or had deformities characteristic of acorn calves (Hart et ah, 1947). The foundation heifers were tested for Bang's disease and found negative, and no other reproduction diseases were found in the herds. Vitamin A deficiency was not found. Similar losses were reported in neigh- boring commercial herds and occurred mostly during the dry-forage period. Most abortions occurred after midsummer, dur- ing the sixth or seventh month of gesta- tion (these were called "dry feed" abor- tions by some stockmen). Woodward and Clark (1959) reported a 3.6 per cent stillbirth loss (from 8,857 births) in Hereford cattle from 1936 to 1957 at the U. S. Range Livestock Experi- ment Station, Miles City, Montana. They were unable to discover any causative factor, but they noted that more males than females were stillborn, that live-born calves were heavier at birth, and that there was a significantly higher number of stillborn calves in the inbred populations. A significantly higher number of stillbirths were recorded in first calvings, and pos- terior presentations and twinning resulted in a higher-than-average number of still- births. Wiltbank et al. (1961), studying beef cattle in Virginia and Louisiana, found that total losses at calving time were larger than those reported by Wood- ward and Clark (1959). They reported that the largest losses in potential calf crops were the result of failure to con- ceive, early embryonic death, and death of calf at, or shortly after, birth. Donald (1963), studying perinatal deaths among calves in a crossbred dairy in Great Britain, found a 14.7 per cent loss in pure- bred heifers and 6.4 per cent in crossbred heifers; corresponding losses for older cows were 2.4 per cent and 3.6 per cent, respectively. Our experiments with breeding herds at the San Joaquin Experimental Range were directed principally toward determining the effects of unimproved range and man- agement practices upon the number of calves produced, weight of calves at wean- ing, and weight of breeding animals. The management practices studied were mainly ( 1 ) feeding cows on range forage alone versus supplemental feeding de- signed to compensate for seasonal nutri- tional deficiencies in natural forage; (2) heavy versus moderate and light stocking; (3) determining how much the breeding herd, originally of ordinary range quality, could be improved by the use of purebred bulls; and (4) rotational versus yearlong grazing (Bentley and Talbot, 1951; Wagnon et al, 1959). 1 Submitted for publication January 19, 1965. 2 See "Literature Cited" for publications referred to in text by author and date. [3] Ascribing different types of calf losses to positive causative factors was difficult as it was not known what normal losses would be under operating conditions set up in the experiments. Various types of such losses have been summarized here for each group of cattle studied, and in studies conducted after 1948 attempts were made to find causative factors re- sponsible for reproduction losses. PROCEDURE The cows used were grade Heref ords bred to purebred Hereford bulls from the Uni- versity herd at Davis. Breeding com- menced annually about December 28 and terminated May 1 with one bull used per pasture; to equalize differences in breeding effects, bulls were rotated annually be- tween major breeding groups. Unless otherwise stated, cows were culled for poor health, poor conformation, or bar- renness; all were culled after they were 10 years old. Calves were weaned about July 1 each year, and cull cows were re- moved and replacement heifers added. The operational year was approximately July 1 to July 1 and consisted of dry- forage, winter, and green-forage periods. Dry-forage and winter periods were com- bined to form a "supplemental period" (about July 1 to February 1) during which most of the experimental groups re- ceived supplements on the range. The green-forage period was called the "graz- ing period" (about February 1 to July 1) and during it the cows subsisted entirely on natural forage. Seasonal variations in forage conditions resulted in some varia- tion in the lengths of the two ma; or periods. Unless otherwise stated, pasture stocking was at a moderate rate. GENERAL SUPPLEMENTAL FEEDING This consisted of 1 pound of cottonseed cake, pellets or meal (43 to 41 per cent protein), per cow daily from the start of the supplemental period until calving commenced (about October 1); protein supplement was then increased to 2 pounds per head daily. Following the first autumnal rainfall that initiated new forage growth, 1 pound of rolled barley per head daily was added to the ration. Occasion- ally, cottonseed pellets were replaced by linseed pellets, and rolled barley by ground milo. Some groups were self-fed by mixing the supplements with salt to regulate daily intake. During some droughty periods when there was a short- age of forage the above supplements were added to, or replaced with, alfalfa hay. MANAGEMENT OF COWS From 1936 to the close of the grazing period in 1948 the major studies involved two breeding herds, A and B. Herd A was hand-fed supplements, while herd B re- ceived no supplements except for one severe winter when a few deaths from malnutrition and exposure occurred. Re- placement heifers for each herd originated within their respective herd. During sup- plemental periods the A herd was in pas- ture 11 in 1936 and 1937, pasture 13 from 1938 through 1941, and pasture 12 from 1942 through 1947. The B herd was in pasture 12 in 1936 and 1937, and in pasture 14 from 1938 through 1947. Dur- ing the 1936-1948 grazing periods, cows in the two herds were divided equally among pastures 1 to 6, with each pasture grazed at a different intensity, varying from heavy to light use. The same cows were returned to the same pasture each year until culled or dead. In 1941 a third breeding herd, C, was established to provide needed additional weaner calves. This herd, which was maintained year-around in one pasture and which received hand-fed supplements, was formed in July 1941 with cows culled from the A and B herds. The herd was in pasture 12 until July 1942, and then con- tinuously in pasture 13 until the start of the 1948 grazing period, when it was moved to pasture 14. During this latter period a creep was provided for the calves [4 PASTURE ROUTINE, 1936-1958 Period Herd Routine July, 1936 to July, 1948 A Regular pasture rotation July, 1936 to July, 1948 B* Regular pasture rotation July, 1941 to July, 1948 C Year-around in one pasture February, 1948 to July, 1957 F Year-around in one pasture July, 1948 to July, 1950 Provisional D Changing routine July, 1948 to July, 1950 Provisional E Changing routine July, 1950 to July, 1953 D Regular pasture rotation; poor repro- duction record July, 1950 to July, 1953 E Regular pasture rotation; good repro- duction record July, 1953 to July, 1958 Breeding Group I Regular pasture rotation; contains D and E herd cows July, 1953 to July, 1958 Breeding Group II pplements on Regular pasture rotation; contains D and E herd cows; pastures fertilized with sulfur the range. * This herd did not receive su and the self-feeder was charged with a mixture of 400 pounds rolled barley, 50 pounds beet pulp and 50 pounds cotton- seed meal. Breeding in 1948 was by a purebred Angus bull until March 12, after which a Hereford bull was used for the remainder of the breeding season. The studies of the A, B and C herds terminated at the close of the 1948 graz- ing period, and the herds were then dis- banded. Major findings resulting from the use of these herds have been reported by Hutchison and Kotok (1942); Bentley and Talbot (1951); and Wagnon et al. (1959). To further study possible ill-effects on reproduction from year-around grazing in one pasture, 12 dry cows were selected from the B herd on February 10, 1948. The cows were designated the F herd and placed in pasture 4 (fig. 1), where they remained continuously until the close of the 1957 grazing period. Supplements were hand-fed through the 1953 supple- mental period and self-fed thereafter. Agricultural gypsum was used to regulate daily supplement intake in 1954 and through the 1955 dry-forage period until illness was encountered. The supplement was then mixed with salt (Wagnon, 1960). A calf creep, charged with the same feed mixture as for C herd calves, was placed in the pasture for the droughty 1949 grazing period. After July 8, 1948, all cows in the A, B and C herds were placed in provisional D and E herds, and these two provisional groups were maintained through 1948-49 and 1949-50 only. Provisional D herd was in pasture 13 for the supplemental period, and in pasture 14 for the grazing period. The provisional E herd was in pasture 1 and pasture 2 for the first por- tion of the supplemental period, and in pasture 1 1 for the remainder of the period. This herd was in pasture 12 for all but about the last 6 weeks of the grazing period, when it was moved to pastures 1 and 2. Both herds were hand-fed supple- ments. Because 1949 was a poor forage year, the bred cows of both herds were moved to the University of California at [5 LEGEND: 1-14 PASTURE NUMBERS HP HORSE PASTURE NA NATURAL AREA I MILE J Fig. 1. Pasture diagram of the San Joaquin Experimental Range, 1948-1958. [6] Davis from July 7 to September 26, 1949. The first-bred heifers remained at the range. Meanwhile, plans were being con- sidered to remove brush and excess trees from pastures 1, 2, 11 and 12 and to treat the pastures with fertilization, rodent control and, possibly, reseeding. Pastures 1 and 2 contained large swale areas and were to be reserved until the last few weeks of the grazing period so that calves pastured in them would have green forage until nearer weaning. The herd in these pastures was to be culled for poor repro- duction. Pastures 13 and 14 would be con- trols, and the pastures and their herd would be managed as in the past. In the fall of 1951 enough pit gypsum was applied to pastures 1 and 2 to supply about 60 pounds of sulfur per acre; in the spring of 1952 soil sulfur was applied to pasture 11 at the rate of 60 pounds per acre; in the summer of 1953 pit gypsum, at the same rate as in pastures 1 and 2, was applied to pasture 12; and in 1954 pit gypsum was again applied to pastures 1 and 2. After the cows were returned from Davis to the range those having a poor reproduction record, or descended from dams with a poor reproduction history, were placed in herd D and rotated be- tween pastures 13 and 14. Cows with a good reproduction history were placed in herd E, which was rotated among pastures 1, 2, 11 and 12. These herds became officially operative in 1950-51 and were continued through 1952-53. Cows in E herd losing a calf from abor- tion, stillbirth, or early death were culled or transferred to the D herd. Replacement heifers originated from their respective herds, but were reared together in other pastures until they were bred; they be- came replacements at the start of the sup- plemental period during which they would first calve. Supplements given to the D herd were self -fed, while those to the E herd were hand-fed. To determine if a copper deficiency could be demonstrated by a change in hair-coat color in late fall and winter, the D herd also received Vi gram of CuS0 4 per pound of supplement fed and 500 grams of CuS0 4 per 50 pounds of salt during the grazing period. In mid- 1953, following abandonment of the proposed improved practices demonstration, the D and E herds were randomly divided. Half of the D herd was placed with half of the E herd to form Breeding Group I and the other halves of the two herds were combined to form Breeding Group II. Both groups were maintained until mid- 1958. Breed- ing Group I was rotated in pastures 13 and 14, and Breeding Group II was ro- tated in pastures 1 , 2, 11 and 1 2. E herd cows losing a calf were not transferred to the D herd when culled. An Angus bull was also turned into pasture 14 at the start of each grazing period to see if pas- ture size and topography had been affect- ing per cent pregnancy when the services of just one bull were available. Replace- ment heifers continued to be selected and reared as previously described for the D and E herds. During the last 4 years of this 5-year period these heifers were used in a study of the effects of a high- protein diet on pregnant heifers; they became replacements after calving. Because of insufficient water in pasture 13, Breeding Group I was hand-fed sup- plements; Breeding Group II was self-fed. Breeding Group I was given a minor- mineral mix to see if the reproduction rate and weaning weights of the calves in the pasture 13 and 14 routine could be im- proved. This mixture was fed at the rate of V2 pound per 50 pounds of salt and consisted of the following: CaHP0 4 , 1014 grams; K 2 HP0 4 , 773 grams; CaCO s , 686 grams; MgS0 4 , 106 grams; Fe citrate, 58 grams; MnS0 4 , 3 grams; KI, 1.7 grams; CaFe, 1 gram; CuS0 4 , 0.6 grams; ZnO., 0.5 grams; and CoCl, 0.2 grams. Heavy reproduction losses in first- calving heifers in parts of California led to a request for information on the effects of feeding a high-protein diet during late gestation. For 4 years, starting in 1954, bred replacement heifers were randomly divided at the start of the supplemental period. A control group was given the usual supplement diet, but protein supple- ment to the other group was gradually in- creased until 8 pounds of cottonseed pel- lets per head was fed daily. This rate was continued until each heifer had calved. [7] All weights (except for suckling calves) were taken after an all-night stand in a corral lot without food and water (Wag- non and Rollins, 1962). A detailed de- scription of the experimental area is given by Hutchison and Kotok (1942). EFFECTS FROM SEASONAL CHANGES IN CLIMATE Variations in monthly distribution of rain- fall, the amounts received, and the mean air temperatures have marked effects on seed germination, subsequent plant growth and per cent of the various species com- prising the dominantly annual-type forage cover. Thus, these factors affect cattle subsisting on the forage (Bentley and Talbot, 1951; Wagnon et al, 1959; Wag- non, 1963). For six of the years 1948-58, annual rainfall was below the longtime average of 17 to 18 inches. In midwinter of each year mean monthly temperatures dropped below 50° F and retarded forage growth, the degree of retardation being dependent on the degree of cold. Figure 2 below shows some possible effects of climatic fluctuations on cattle growth as indicated by variations in aver- age weight losses and the gains of the unsupplemented weaner heifers for the annual supplemental and grazing periods. These weight changes were a reflection of the changing nutritive values of available forage and not its abundance (except in [8 800 700 i- 600 Ul * 500 >- o o CD »•> 400 Q Z 3 O QL UJ o < UJ < 800 700 £ 600 o UJ * 500 Q s 400 800 700 600 500 400 -i — i — i — i — i — i — i — i — i i r 1952-53 10 head 15.71 1954-55 10 head 16.73 1956-57 10 head 14.52 J I I I I I I I L t — r i — i — r i — i — r 1953-54 10 head 15.58 1955-56 10 head 26.45 1957-58 10 head 31.95 .1 I I I l_ 7 8 9 10 11 12 1 2 3 4 5 6 7 MONTH 9 10 11 12 1 2 3 4 5 6 Fig. 2. Average weight curves (solid line) for unsupplemented weaner heifers with monthly rainfall totals (bars) and the monthly mean temperature (dotted line), 1948-1958. Total annual rainfall is given in the lower right corner of each graph. Average weight gains and losses for the supplemental and grazing periods are given above weight curves; maximum average weight loss during supplemental period only is given below the line. 9] midwinter), as a light stocking rate was used. Although breeding cows used in this study received supplements calculated to meet their minimal nutritive requirements, it should be reemphasized that the breed- ing season commenced about January 1 when range forage conditions were often poorest. The study shows that natural con- ditions in these poor years did not ad- versely affect per cent pregnancy ob- tained. Thus, the supplemental feeding program was evidently fulfilling its ob- jectives. REPRODUCTION COMPARISONS OF SUPPLEMENTED AND UNSUPPLEMENTED COWS Table 1 shows that supplemented herd A had a larger percentage of cows conceiv- ing, and that they weaned more pounds of weaner calf per cow than did unsup- plemented herd B or supplemented herd C cows. Since one-third of the cows in herds A and B had to close-graze during grazing periods, some decrease in concep- tions could be expected. In the B herd, lack of supplemental feeding was the major cause of the marked reduction in conception rate. The 17.6 per cent of dry cows in herd C — a herd maintained year- around in one pasture at a moderate stocking rate — is excessive, and causative factors remain unknown. The greater age at weaning of the A herd calves indicates that their dams were able to conceive earlier than the cows of the other two herds, which had identical breeding sea- sons. Although weaning weights of calves from supplemented herds exceeded those of the unsupplemented herd, the actual difference noted between calves from the two supplemented herds was not ex- pected; in fact, differences could be ex- pected to be opposite from those actually obtained, because none of the C herd cows was subjected to close grazing. It is possible that heredity might be in- Table 1 REPRODUCTIVE DATA ON SUPPLEMENTED A AND C HERDS AND UNSUPPLEMENTED B HERD, 1936-1948 Item Total possible matings Per cent cows dry , Per cent cows pregnant Calves weaned Per cent calf crop Calves lost prior to weaning Per cent calves lost Abortions Stillbirths Per cent abortions and stillbirths Losses from dystocia Losses due to death of dam Losses from other causes* Average calf weaning age (days) Average calf weaning weight (lbs.)t- . . Pounds weaner calf produced per cow 1936-48 A Herd B Herd 448 10.5 89.5ot 367 81. 9o 37 9.2 10 14 6.0 3 3 7 238c§ 462c 378 456 25.0 75.06 302 66.26 41 12.0 7 11 5.3 5 8 10 228d 407d 1941-48 A Herd B Herd C Herd 267 7.9 92.1a 225 84.3a 22 8.9a 6 8a 5.7a 2 5 238c 449c 378 270 23.3 76.76 179 66.36 29 14.0a,6 5 11a 7.7a 2 3 8 227d 394a,d 261 148 17.6 82.46 100 67.66 22 18.06 2 146 13.16 2 1 3 224d 4186,d * Illness, accidents, etc. t Adjusted to 240 days of age. t Mean values in the same line and same time period but having different letters a or 6 differ significantly § Mean values in the same line and same time period but having different letters cord differ eignificantly (P < p.01). [10] volved in some of the abortions and still- births shown in table 1, because in some instances these losses occurred in several successive generations. Early calf deaths which were also observed could be re- lated to losses from abortions and still- births; some of the early deaths occurred shortly after birth, while others occurred in a few weeks. In many instances the calves appeared to be of normal size and health prior to death. As culling was based on poor con- formation, poor health, barrenness, and age, and not on calf-loss or failure to conceive in one season, many of the losses encountered may be representative of a herd where poor production or reproduc- tion failure of a cow were disregarded when selecting her daughters as replace- ments. To study possible effects from culling cows that failed to wean a calf each year, an analysis was made of A and C herd data. From 1935 to 1947-48, 215 cows received supplements. They had 1,213 possible pregnancies (5.6 per cow) and weaned an 80.4 per cent calf crop. Sixty- eight cows (31.2 per cent) weaned a calf each possible pregnancy; they averaged 5.5 pregnancies per cow and weaned a 100.3 per cent calf crop (1 pair twins). Each of the remaining 147 cows failed to wean one or more possible calves; if failure to do so had been been the cri- terion for culling, these cows would have been culled after an average 2.7 possible pregnancies per cow. Per cent calf crop, including their first loss, was 64.0 (in- cluding 3 pair of twins). Of the 147 cows, 121 were retained for an additional aver- age 3.6 possible pregnancies, and during this latter period they weaned a 78.2 per cent calf crop. Thus this group, which could have been culled for first failure to wean calves, produced a higher percent- age calf crop after first-calving failure. Of total cows, 29 heifers failed to wean a calf following their first breeding. These animals were maintained in the herd through an average 5.3 possible pregnan- cies, and during this period they weaned only a 61.7 per cent calf crop. The above summation is not indicative of results obtained when cows are culled for failure to wean a calf, and when re- placements are from cows able to repro- duce regularly under existing range con- ditions. It is quite possible that the exces- sive number of reproduction losses in the C herd were due to unknown environ- mental factors that could be corrected by proper managerial treatment. YEAR-AROUND GRAZING IN ONE PASTURE Observations of the F herd in pasture 4 year-around extended through nine calf crops (table 2), and failure to wean a calf was not a criterion for culling. The results show a higher average per cent pregnancy and calf crop, and higher average calf- weaning weight and age than had been ob- tained with A and C herds. Pasture 4 contained a higher percent- age of area having steeper southern ex- posures than did the other herd's pas- tures. Pasture 4 evidently was warmer in winter and grew more early forage than did other pastures; F herd cows and calves pastured there gained weight sooner and faster than did animals in other pastures. The average reproduction efficiency of the F herd was higher than that of the A and C herds, but this was at least partly due to the marked decrease in per cent of dry cows (table 3). Average F herd calf losses after conception were similar to those of the A herd (table 1 ) and losses from abortion, stillbirths and early deaths were lower than those of the C herd. These results indicate that year-around grazing in one pasture is not necessarily the cause of slower rebreeding, lower con- ception, higher reproduction losses, and lighter calf-weaning weights. 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P- S3 >> d CP co |q d ^ •£ eu t» CD d d o — •I a a^ a -a -ox II UO occoi-hi-~coo^-o 11j in co n co Q 00 £ O OS < i — 1 4 & OS N £ £ << S > P o cX! r. PH £ rt 1— 1 z Q x W Ph H ^ H W S W w J k; Oh Ph H P H m w Ph Ph ^ w w ^ Ph o H >-H — < Ph P o Ph* £ o c o k; £ > uj h^ 2 — iCNOOO oooooooo Ol OO O CN OOOOOOOOOOO £i .5* co CJ a> £ X3 W) p « rs 5 §•■§ t-i o §. M u 1—3 T3 CO ^ CD CD 0} *~* CD CD S M M M S M » -g co es 03 -g g rt S CD CD CD S CD CD 3 > 55 <3 fl ° S O CO 4> * 55 * £ .2 8' be O CD -IJ -IJ £ Tl < O 2 -3 . J) 05 CO g££ I I I *£> •£ aj CD O O < Vt ... D + E herd heifers 300 200 - 4r * - 1 1 1 1 1 1 1 I 1 I 1 l Jan. Feb. Mar Apr. May June July 1949 Aug. Sept. Oct Fig. 3. Average weight curves of F herd calves, and D and E herd heifers, showing decreased growth after weaning. [21] year period, while a large number of dry cows and a marked retardation in re- breeding was noted during the fifth and sixth years after the cows had become well-accustomed to their routine. Thus, these reproduction losses do not appear to be the result of changing routine. In the F herd, formed with 12 dry B herd cows in the middle of the 1948 breeding season, most of the cows had conceived just prior to their change of routine. The high average production of this herd is shown in tables 2 and 3 ; how- ever, these cows showed an average weight loss of 220 pounds during their first supplemental period in the new en- vironment, and completed the 1948-49 period weighing an average 117 pounds less than at the start. Their first rebreed- ing in this pasture was markedly below that of subsequent years, as shown by the average 219 days calf weaning age for 1949-50. During studies of the A, B and C herds an occasional calf apparently grew nor- mally through the suckling period but after weaning would not gain weight as did similarly treated calves. Some of these calves went into a slow decline and died from what was subsequently termed "de- cline disease." These calves were not identified prior to weaning; they occurred in all three herds, but appeared more fre- quently in the early years of the C herd. Six (5 heifers and 1 steer) of the 10 calves weaned in the first calf crop (1948-49) of the F herd were found to be afflicted with decline (fig. 3), but re- tardation was mild and the calves ap- parently performed normally after the onset of winter. Causes of the condition remained unknown. In 1948-49, provisional D herd (formed with 2 A herd cows, 24 C herd cows and 23 bred replacement heifers) was rotated between pastures 13 and 14, and 49 per cent of the herd continued to be supplemented in a pas- ture in which they were formerly main- tained year around. At the same time, provisional E herd (formed with 26 A herd and 18 B herd cows) was rotated Table 8 WEIGHT CHANGES, SUPPLEMENTATION DATA, AND WEANER-CALF PRODUCTION FOR PROVISIONAL D AND E HERDS, 1948-50 TRANSITIONAL PERIOD Item 1948-49 D Herd E Herd 1949-50 D Herd EHerd Total number cows Start of supplemental period, average weight (lbs.) End of supplemental period, average weight (lbs.). Average weight loss (lbs.) End of grazing period, average weight (lbs.) Average weight gain (lbs.) Average weight gain or loss for year (lbs.) Per cent cows pregnant Retained placentas Per cent calf crop Average calf-weaning age (days) Average calf -weaning weight (lbs.) Average pounds of weaner calf produced per cow. . Length of supplemental period (days) Total supplements fed per cow: Cottonseed pellets (lbs.) Rolled barley (lbs.) Alfalfa hay (lbs.) 918 121 993 75 -46 100.0 8 79.6 241 391 311 230 251 55 l,050f 44 1,032 929 103 1,095 166 +63 70.5 2 59.1 229 430 254 232 270 58 l,103t 54 1,007 947 60 1,119 172 + 112 94.4 5 63.0 240 483 304 229 1 84 1,022§ 37 1,036 910 126 1,099 189 +63 94.6 6 75.7 247 492 372 231 1 84 670§ * Weight data based on cows present at all three weighings annually. t Poor quality hay due to rain damage. X Cows on pasture at Davis the first 84 days (includes travel). § Used as supplement after 11/10/49 because of shortage of range forage. [22] between pastures 1,2, 11 and 12, and the pasture routine was new except for the fact A herd was formerly in pasture 12 for its supplemental period. Table 8 gives supplementation, seasonal weight changes of the cows, and weaner calf production during this time; table 9 gives reproduc- tion data. As the cows had been bred prior to being placed in these provisional herds, the marked difference in per cent of dry cows in 1948-49 is happenstance. The high average calf-weaning ages in 1949-50 show that the cows rebred early. The data show a marked increase in calf losses from abortions, stillbirths and early deaths in both herds, but losses from dystocia, death of dam, and other causes were low. In 1949-50, 77 head of provisional D and E herd cows were moved to Davis, California, on July 11 and returned to the range on September 26. At Davis the cows were placed on barley stubble until August 1, when they were moved to Sudan grass pasture. One cow aborted on August 8, four on August 13, three on August 14, and one on September 9; the cause was not determined and all cows were found negative to the Brucella abor- tus agglutation test. There had been re- ports of heavy abortion losses from dis- ease in some herds that had been moved into adjacent foothills for the first time; later this disease was diagnosed as epi- zootic bovine abortion (Howarth et ah, 1956), and it became known as "foothill abortion." When provisional D and E herd cows were returned to the range just prior to the start of their regular calving period, 17 head of provisional D herd cows were transferred to the new E herd; the re- mainder were kept in the new D herd. At the same time, 17 provisional E herd cows were transferred to the new D herd and the others remained in the new E herd. These new herds did not become operative until mid- 1950 after they had dropped the calves they were carrying and had been rebred. Table 9 shows that there were more losses from stillbirths and early deaths. If there were effects from changing rou- tine in late 1949 at the establishment of the new D and E herds, they are shown in the 1949-50 data (tables 8 and 9), Table 9 REPRODUCTION DATA FOR PROVISIONAL D AND E HERDS, 1948-50 TRANSITIONAL PERIOD Item 1948-49 1949-50 DHerd E Herd DHerd EHerd Cows possibly bred 49 100.0 39 79.6 10 20.4 2 5 1 16.3 1 1 241 391 311 44 29.5 70.5 26 59.1 5 16.1 1 2 2 16 1 229 430 254 54 5.6 94.4 34 63.0 17 33.3 9* 5 1 29.4 1 1 240 483 304 37 Per cent cows dry 5 4 Per cent cows pregnant 94.6 Calves weaned 28 Per cent calf crop 75.7 Calves lost prior weaning 7f Per cent calves lost 20 Abortions 4* Stillbirths o Early deaths 2 Per cent abortions, stillbirths and early deaths . . 17.1 Losses from dystocia 2t Losses from death of dam Losses from other causes Average calf weaning age (days) 247 Average calf weaning weight (lbs.) 492 Average pounds weaner calf produced per cow 372 * Of nine cows aborting at Davis, three were not identified bv individual number. Two were assigned to D herd and one to the E herd. t A pair of twins counted as one in total calves lost. r 23 1 as the cows had quite likely adjusted to their new groupings by the time they were rebred for the 1950-51 calving. There was no evidence of effects from routine changes at the formation of Breeding Groups I and II in mid- 1953. Calf losses for herds D and E following conception were quite similar to those previously re- ported for the A, B and F herds (tables 1 and 3). CREEP FEEDING The routine of the C herd was changed at completion of calving the last year of its existence when the herd was moved to pasture 14 for the 1948 grazing period. Due to droughty conditions a creep was established for the calves. Average daily consumption of supplements per calf was 1.2 pounds the first 60 days when forage was in early growth stages, 2.1 pounds the next 49 days while forage was matur- ing and drying, and 4 pounds the re- mainder of the period when forage was dry. Average total consumption of con- centrates per calf was 232 pounds. Dur- ing the feeding period these calves made an average total gain of 221 pounds, as compared with 257 and 260 pounds, re- spectively, for calves of the A and B herds that were not creep fed. The differences were significant: (P < .01). Although supplement consumption of the C herd calves was lower than expected (possibly affected by pasture size and topography) it seemed strange that their weight gains would be less than those of the A and B herds. To further observe results obtained with the creep, it was moved to pasture 4 for the first calf crop of the F herd dur- ing the droughty 1949 grazing period. (The F herd had been moved to this pas- ture during their breeding for this calf crop.) Average daily consumption of supplements per head, for forage periods similar to those for the C herd calves, was 1.1 pounds the first 70 days, 4.2 pounds the next 48 days, and 6.1 pounds for the remainder of the period. Average total consumption of supplements per calf for the period was 475 pounds. Dur- ing the feeding period these calves made an average total gain of 253 pounds as compared with 199 and 227 pounds, re- spectively for the provisional D and E herd calves (routines of whose dams had been changed in mid-pregnancy) that were not creep fed. These gains differed significantly: (P < .01). The smallest average gain of provisional D herd calves occurred in pasture 14, where C herd calves had been creep fed the previous year. Therefore, pasture 14 itself ap- peared to be the cause of the low calf- weaning weights. EFFECT OF MINERAL SUPPLEMENTATION Copper was fed to the D herd in 1950- 53, but there was no discernible improve- ment in hair coats, reproduction, or calf- weaning weights (tables 3 and 4). Analy- sis of liver samples from cows culled at the close of this period showed 57 ppm of copper, as compared to 35 ppm in the livers of cows receiving no copper. Thus, a copper deficiency did not exist. Feeding Breeding Group II a mix of minor minerals during 1953-58 produced little evidence that D herd cows of this group performed better than they did when in the 1950-53 D herd (tables 4 and 5). There was an improvement in per cent conception, but it is not known if this was because of the minerals — the per cent of dry cows was still excessive. There was no improvement in per cent of calves lost, in faster rebreeding, or in calf-weaning weights. REGULATING SUPPLEMENT INTAKE WITH SALT From the time we commenced mixing salt with concentrates to regulate the daily intake of these supplements by cat- tle, we received reports from the field [24] us © >o © "-S CO CO CO-^fOJiCKOOOOCMCO"*! C Ct-HXTf»MNMnCNO cr> CO H O o o o o -* o O^fO^H^OOOOOO s o io >o «o o CO l> t~ ■** ^— . . . o CO o f~oj**oeo©r-~©ot^© ■»*< CO CO CO t- o # >o t- * O r-t ■**tlOlO-<*> 8 g T3 s 53 00 ■5 os 8 fcw "H 00 .S B 3 -Q o rt S -g o TS £ '-3 >, u CD p co -a a; a -t- e ons, rom foth l08t wea u X a £ •« i O i m , >, O O « § 2 S 3 C fl e 3 S ° i StS >>g pp gg o c ioj)^3«sj)o!ojj)ai E- C ) p 0. p. < or ft 1 & 4 C ) c ) P- 1 P. that the practice resulted in lowered breeding efficiency. The E herd was hand- fed supplements in 1950-53, and the E herd in Breeding Group II (same pasture routine) were self -fed supplements in 1953-58. The lack of significant differ- ences in reproduction performance of these two groups (tables 4 and 5) indi- cates that the high salt consumption re- sulting from the use of salt to regulate daily intake of supplements does not lower reproduction efficiency. ABORTIONS, STILLBIRTHS, AND EARLY-CALF-DEATH LOSSES From 1938 to 1958, out of 185 cows los- ing calves prior to weaning 135 lost one or more calves from abortions, stillbirths and early deaths. Table 10 shows that the per cent losses from abortions, stillbirths and early deaths were similar for all age classes. Thus, it appears impossible to completely eliminate the types of calf losses noted in this report. However, cull- ing the cows which had such losses in- creased the calf crop about 8 per cent, while in some instances changing an estab- lished routine during pregnancy appeared to increase these losses. SUMMARY In a 12-year study of effects of supple- menting the diets of range cows, supple- mented herds averaged 10.5 per cent dry cows, 6.0 per cent loss from abortions and stillbirths, and 3.2 per cent loss from dystocia, death of dam, and other causes; unsupplemented cows averaged 25.0, 5.0, and 7.0 per cent, respectively. The exces- sive numbers of dry cows in each group may largely be due to the effects of close grazing on one-third of the cows in each group, plus the lack of needed supple- ments in the unsupplemented group. In a 10-year investigative period which fol- lowed the first study, a study of the ef- fects of climatic conditions on weight gains and losses indicated that the rates of protein and energy supplementation used in the program were adequate for good conception. Another supplemented herd, main- tained year-around in one pasture at a moderate stocking rate, averaged 17.6 per cent dry cows, 13.1 per cent abortions and stillbirths, and 4.9 per cent loss from dystocia, death of dam, and other causes over a 7-year period. Excessive losses from failure to conceive, abortions, and stillbirths were attributed to year-around grazing in one pasture. A second supple- mented herd, maintained year-around in another pasture over a 9-year period, averaged 2.9 per cent dry cows, 6.9 per cent abortions, stillbirths and early calf deaths (now considered related to the abortion-stillbirth problem), and 3.9 per cent loss from dystocia, death of dam, and other causes; in addition, cows of this group bred more readily than those of the 7-year group. Thus, it appears that year-around grazing in one pasture is not necessarily the cause of a high per cent of dry cows and an increase in the abortion, stillbirth and early calf death rate. Supplemented cows with poor repro- duction histories and not culled for losing a calf had, in a two-pasture rotation sys- tem for 3 years, an average 18.7 per cent dry cows, 3.6 per cent abortions, still- births and early calf deaths, and 4.3 per cent loss from dystocia, death of dam, and other causes. Another supplemented group of cows having good reproduction histories and culled for losing a calf had, in a three-pasture rotation system for 3 years, an average 2.5 per cent dry cows, 5.0 per cent abortions, stillbirths and early calf deaths, and 5.1 per cent loss from dystocia, death of dam and other causes. Lack of sufficient bull power was [26] possibly in part to blame for the high per cent of dry cows in the first group. After placing half the cows having good reproduction histories with half the cows having poor reproduction histories in the latter's two-pasture rotation system for a 5-year period, the latter group aver- aged 10.9 per cent dry cows, 6.5 per cent abortions, stillbirths and early calf deaths, and 5.7 per cent loss from dystocia, death of dam and other causes; the cows with good histories averaged 6.3, 6.7 and 4.8 per cent, respectively. When half the cows having poor reproduction histories were placed with half those having good reproduction histories in the latter's three- pasture rotation system for the 5-year period, the latter group averaged 3.2 per cent dry cows, 4.9 per cent abortions, stillbirths and early calf deaths, and 2.5 per cent loss from dystocia, death of dam and other causes; the group having poor histories averaged 4.5, 7.1 and 0.8 per cent respectively. Thus, cows having good reproduction histories had an increase in calf losses when placed in the two-pasture rotation system, but cows having poor re- production histories had a decrease in calf losses when placed in the three-pas- ture rotation system. The marked reduction in per cent dry cows between the groups in the two-pas- ture rotation system for the 3 -year and 5-year period does not appear attributable to the addition of another bull during the second period, as the Angus bulls sired only 3.1 per cent of the calves. In the three-pasture rotation systems, sulfur fer- tilization and adjustment of the pasture rotation to take advantage of late-matur- ing forage in the few weeks prior to weaning increased pasture carrying ca- pacity, weights of cows, and calf-weaning weights; all this was expected. Feeding a high amount of protein to first-calving heifers through the last 3 or 4 months of gestation period did not cause them to have heavier calving losses or to differ in calf-weaning weights from heifers supplemented in the usual manner. Changing the cattle's established rou- tine or environment during late preg- nancy appeared to increase calf losses during a 2-year period. In the first year, cows did not leave the range and there was a 16.2 per cent loss from abortions, stillbirths and early calf deaths. In the second year during which cows were moved off the range for 80 days prior to calving, these losses were 24.4 per cent — this includes an 11.7 per cent abortion loss while the cows were away; losses from dystocia, death of dam and other causes were only 2.5 and 3.5 per cent, respectively. Factors arising from chang- ing routine may have also been involved in a decline condition of weaned calves: 60 per cent of the first calf crop of a herd whose routine was changed during the breeding season was afflicted, and creep-fed suckling calves from a herd whose routine was changed at the end of the calving period gained less weight than did similar calves not creep fed in two herds accustomed to a pasture change at that time of year. There was no evidence that salt used to regulate daily consumption of self-fed supplements lowered breeding efficiency of cows.There were no apparent benefits from feeding copper or a minor-mineral mixture. Reproduction records of all the cows receiving supplements over the 22-year period of study showed an average total loss of 20.9 per cent. Of this, 9.2 per cent were dry cows, 8.0 per cent abortions, stillbirths and early calf deaths, and 3.7 per cent were dystocia, death of dam and other causes. Losses from failure to con- ceive and from abortions, stillbirths and early calf deaths show the greatest vari- ability between years and experimental herds. These losses probably have the greatest possibility of being reduced by proper management. However, most losses from dystocia, death of dam and other causes probably were unavoidable. [27] LITERATURE CITED Bentley, J. R., L. R. Green and K. A. Wagnon 1958. Herbage production and grazing capacity on annual-plant range pastures fertilized with sulfur. J. Range Mgmt. 11(3) : 133-40. Bentley, J. R., and M. W. Talbot 1951. Efficient use of annual plants on cattle ranges in the California foothills. U. S. Dept. Agr. Cir. 870:1-52. Donald, H. P. 1963. Perinatal deaths among calves in a crossbred dairy herd. An. Prod. 5(1) :87- 95. Farnsworth, Freeland 1962. Calf crop raised from 45 to 94.2%. Pacific Stockman 28(5 & 6) :9-ll. Green, L. R., K. A. Wagnon and J. R. Bentley 1958. Diet and grazing habits of steers on foothill range fertilized with sulfur. J. Range Mgmt. 11(5) :221-27. Hart, G. H., H. R. Guilbert, K. A. Wagnon and H. Goss 1947. Acorn Calves: A nonhereditary congenital deformity due to maternal nutri- tional deficiency. Calif. Agr. Exp. Sta. Bui. 699: 1-24. Howarth, J. A., J. E. Moulton and L. M. Frazier 1956. Epizootic bovine abortion characterized by fetal hepatopathy. J. Amer. Vet. Med. Assn. 128(9) :441-49. Hutchison, C. B., and E. I. Kotok 1942. The San Joaquin Experimental Range. Calif. Agr. Exp. Sta. Bui. 663:1-145. Wagnon, Kenneth A. 1960. Agricultural gypsum as a regulator for self-feeding cottonseed meal to cattle on the range. J. Range Mgmt. 13(6) : 279-82. 1965. Social dominance in range cows and its effects on supplemental feeding. Calif. Agr. Exp. Sta. Bui. 819:1-32. Wagnon, K. A. 1963. Behavior of beef cows on a California range. Calif. Agr. Exp. Sta. Bui. 799:1-58. Wagnon, K. A., J. R. Bentley and L. R. Green 1958. Steer gains on annual-plant range pastures fertilized with sulfur. J. Range Mgmt. 11(4): 177-82. Wagnon, K. A., H. R. Guilbert and G. H. Hart 1942. Experimental herd management. Pp. 50-82 in: Hutchison and Kotok, 1942. 1959. Beef cattle investigations on the San Joaquin Experimental Range. California Agr. Exp. Sta. Bui. 765: 1-71. Wagnon, Kenneth A., and W. C. Rollins 1962. Factors affecting fill and consequently overnight shrinkage in range cattle. J. Range Mgmt. 15(3) : 158-61. Wiltbank, J. N., E. J. Warwick, E. H. Vernon and B. M. Priode 1961. Factors affecting net calf crop in beef cattle. J. Animal Sci. 20(3) :409-15. Woodward, R.R., and R. T. Clark 1959. A study of stillbirths in a herd of range cattle. J. Animal Sci. 18(1) :85-90. I2m-2,'66(F9222)