A. s. NT. bTsIiéeié OF TEXAS BULLETIN NO. 657 TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR College Station, Texas AUGUST 1944 INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES ON FINENESS OF FIBER, FLEECE WEIGHT, STAPLE LENGTH, AND BODY WEIGHT J. M. JONES, W. H. DAMERON, S. P. DAVIS, B. L. WARWICK, AND R. E. PATTERSON Division 0f Range Animal Husbandry AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS GIBB GILCHRIST, President E03-844-850O-I1180 ..~._r.._“1i_i\ . Registered Rambouillet rams bred by Ranch Experiment Station (Substation No. Fig. 1. 14), representing both B and C types used in this study. wx-wrr-“vmmr vqmyw»tws-~ '- The study reported in this bulletin relates to the influence 0f age, fertility. and body type in Rambouillet ewes on fleece weight, length of staple, fineness 0f fiber and body weight. Heaviest scoured fleeces were produced during the third age year, however when considered on either an unscoured or scoured b-asis the differences in production of fleeces during the third and fourth age years were not significant. There was however a gradual decline in fleece weight after the fourth age year. Significant differences of 0.53 and 1.18 pounds in clean weight and grease weight. respectively were observed between the four and eight year old ewes. Staple length was greatest during the first age year. all adjusted t0 365 days growth. There were nosignificant differences in staple length during the second, third and fourth age years. By the sixth age year however, staple length had decreased approximately 0.3 inch and by the eighth age year 0.44 inch, or 18 per cent. Fertile ewes, or those producing lambs during the year, produced wool that averaged 0.08 inch shorter and averaged 0.27 pound less scoured wool than ewes that did not lamb during the year. The diameter of fiber, or fineness of the wool fiber, produced during the first age year averaged slightly but significantly finer than in later age years. After the first year diameter changed so slightly as to be of no practical importance. Body type exerted considerable influence on various characteristics of the wool fiber. The C type, or relatively smooth bodied ewes, pro- duced fleeces that had significantly greater length of staple, finer and more uniform fibers than B type ewes. Accordingly the fleeces from the C type ewes had a higher commercial value. There were no significant differences in scoured fleece weights pro- duced by the B and C type ewes. However, on an unscoured basis, the fleeces produced by B type ewes averaged approximately one pound heavier than those produced by C type ewes. Shrinkage of the fleeces from the B type ewes averaged 62.9 per cent as compared with 59.4 per cent shrinkage from the C type ewes. There were no significant differences in body weights between the plain bodied and the wrinkly or folded types used in these studies. CONTENTS 2s ‘i PAGE Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Definition of Terms Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Fertility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Flock Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. '7 Breeding System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Methods of Sampling.- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Method of Measuring Staple Length. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Method of Measuring Diameter of Fiber . . . . . . . . . . . . . . . . . . . . . . .. 9 Method of Scouring Individual Fleeces . . . . . . . . . . . . . . . . . . . . . . . .. 10 Statistical Treatment of Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Results of Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Influence of Age of Animal on Fleece Weight . . . . . . . . . . . . . . . . . .. 11 Influence of Age of Animal on Length of Staple . . . . . . . . . . . . . . . .. 13 Influence of Age of Animal on Diameter of Fiber . . . . . . . . . . . . . . . . 14 Influence of Age of Animal on Body Weight . . . . . . . . . . . . . . . . . . .. 16 Influence of Staple Length on Diameter of Fiber . . . . . . . . . . . . . . .. 16 Influence of Fertility on Fleece Weight and Shrinkage . . . . . . . . . . .. 17 Influence of Fertility on Staple Length . . . . . . . . . . . . . . . . . . . . . . . .. 19 Influence of Fertility on Fineness of Fiber . . . . . . . . . . . . . . . . . . . . . . 19 Influence of Fertility on Body Weight . . . . . . . . . . . . . . . . . . . . . . . . .. 20 Influence of Body Type on Fleece Weight and Shrinkage . . . . . . . . .. 20 Influence of Body Type on Staple Length . . . . . . . . . . . . . . . . . . . . . . .. 22 Influence of Body Type on Diameter of Fiber . . . . . . . . . . . . . . . . . . .. 22 Influence of Type on Body Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23 Influence of Type of Rambouillet Rams on Shrinkage, Staple, _ Length, and Diameter of Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23 Correlation of Certain Fleece Characters at the Different Ages.. 25 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 28 30 References INFLUENCE OF AGE, TYPE AND FERTILITY IN RAM- BOUILLET EWES ON FINENESS OF FIBER, FLEECE WEIGHT, STAPLE LENGTH, AND BODY WEIGHT J. M. Jones‘, W. H. Dameron’, S. P. Davis“, B. L. \Varwick4, and R. E. Patterson“ History has not recorded accurately the use of wool as an article of ap- parel, however its use is believed to have been co-extensive with the history of man. Wool for a long period of time has been considered a complete or perfect fiber, consequently very little research aimed toward its improve- ment was undertaken until comparatively recent years. The wide develop- ment of competing fibers, the result of highly technical and specialized research, in recent years however has focused attention on the need of ex- panded study cf all of the standard fabrics, and wool is beginning to re- ceive the attention it deserves. A large percentage of the earth’s untilla- ble surface has throughout history been devoted to the production of animal fibers and meat, and such usages of those areas should in the interest of the security of our pastoral industry be continued. During the early years of the range sheep industry in Texas, wool pro- duction was the principal objective of the sheep owners, and since the general belief at the time was that Merinos and Rambouillets carrying a relatively heavy development of skin folds or wrinkles produced heavier fleeces, the general tendency was in the direction of medium heavy to heavy skin folded types. However, as time passed the demand for mutton and lamb increased and range breeders found to their disappointment that the sheep carrying heavy skin folds and body wrinkles were discriminated against by feeder buyers.- The Merino and Rambouillet range breeders were immediately placed in a predicament. They Wanted to produce a type of lamb that would not be discriminated against by feeders yet at the same time they desired not to sacrifice too much fleece weight and quality in their shift to a smoother bodied type. Research workers at this station, realizing the scarcity of definite in- formation on the entire subject relating to comparative weights, lengths, and finenesses of wool produced by relatively smooth bodied Rambouillet sheep as compared to those carrying various degrees of skin folds, began an inheritance study in 1918. One of the principal objectives was to gain some further definite information on. diameter of wool fiber and fiber length in relationship to age of animal. A still further objective was the possi- ‘Chief, Division of Range Animal Husbandry, TAES. “Superintendent, Ranch Experiment Station, TAES. 3Wool and Mohair Specialist, TAES. ‘Animal Geneticist, TAES. _ ‘lAssistant Professor, Genetics, Texas A. & M. College. 6 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION bility of the development of a relatively smooth bodied Rambcuillet pos- sessing the ‘desired fleece characteristics which could be maintained with- out having to resort to the use of sires or dams of heavy skin fold develop- ment for the purpose of maintaining unscoured fleece weight. The results reported in this bulletin relate specifically to the influence of age, type and fertility of Rambouillet ewes on (a) fleece weight and shrinkage, (b) staple length, (c) fineness of wool fiber, and (d) body weight. A - PROCEDURE The records used in this study were taken from all B and C type, reg- istered Rambouillet ewes maintained at the Ranch Experiment Station located in Edwards and Sutton counties near Sonora, for the period 1923- 1940 (18 years) inclusive. The sheep were grazed on a range affording a mixed grassland type of vegetation consisting largely of curly mesquite grass and Buffalo grass, winter grasses and weedy plants and characterized by numerous small thickets of live oak, shin oak, and miscellaneous brush. Light-shearing, open-fleeced and otherwise undesirable animals were iemoved from the Fig. 2. B type (medium) Rambouillet Ram. A..sl~ml...m.a.m_ul..a.._a.._l..a.4 -.__A¢>4\4.k_ , ,,__ saw...“ \_n44n1 ' INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 7 experiment from time to time, the usual procedure being to cull them at the yearling age. The annual rainfall during the period 1923-1940 inclusive averaged 23.90 inches although the variation was pronounced during certain years. In 1923 the rainfall was 31.65 inches and in 1933 it dropped to 13 inches, in 1934 to 12 inches, then in 1935 it reached a high of 41.50 inches. The sires used in the breeding flock were registered and perhaps slightly better than the average for the area. The ewe -fiock was predominantly C - type, although a number of B type ewes believed adequate to provide in- formation essential for comparison were maintained for research purposes. Definition of Terms Used When this study began there was no recognized standard of perfection for the breed. The B type was defined as “a comparatively ~heavy folded _ Rambouillet carrying several large neck folds one or more of which ex- tended prominently over the top of the neck, and further showing one or more skin folds back of the elbow joint, on the sides, at the tailhead, and on the thighs.” The C type was defined “free or comparatively free from skin folds upon any portion of the body.” Animals with cne or more ripron folds none of which extended prominently over the top of the neck, and which were free from folds on other parts of the body were designated as C type animals. Fertility The designations refer to ewes that dropped lambs or did not drop lambs respectively for the season corresponding to the given age. N0 separation has been made as to whether the ewes nursed lambs during the previous season, though none of the ewes used in this study were chronically sterile oxer a prolonged period. Flock Management The ewes were, except (luring the breeding and early lambing season, grazed together on the same range. The natural vegetation varied some- what from season to season in accordance with rainfall. In some growing seasons the range vegetation was abundant and succulent while in others the vegetation was so scarce that the ewes were definitely on a level of sub-optimal nutrition. A supplement cf cottonseed cake was usually fed to all registered ewes during short periods before lambing started. Those which lambed continued to receive supplementary feeds consisting of cot- tonseed cake, alfalfa hay, or sorghum fodder or silage for a period of several weeks after lambing. Since nutrition is known to exert a marked influence on fleece weight it is considered essential to provide suflicient supplementary feed to adequately nourish the breeding flocks in the area during a portion of the winter season. The stud rams used during the course of this study were handled in a manner similar to the ewes although in some instances lambs considered 8 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION particularly promising as studs were fed concentrates and hay in dry lot following Weaning. Ewes remaining in the flock after the most undesirable individuals had been culled were bred to lamb at two years old. Rigid selection was not practiced since it was believed that such a procedure would react unfavorably on the investigations. Several of the best ram lambs were retained in the flock and developed for prospective stud pur- poses while at the same time a relatively large number was disposed of as range rams. For the most part, in accordance with customs in the area, the registered rams were disposed of in the fleece, hence it was not prac- tical to obtain production records of the representative yearling‘ sale rams. Beginning in the late twenties, bitterweed (Actinea odomta), a plant which is poisonous to sheep, encroached heavily on the range pastures of the Ranch Experiment Station, and as in other flocks grazing on similar infested ranges in the area, the production of the flock under study has been unfavorably influenced from the standpoints of body weight and production of wool during the period 1928-1940. Measures for the control of internal parasites did not become necessary until 1925, after which time systematic treatment for the common stomach "worm, (Haiemonchzzs contortus) was generally necessary. Fig. 3. C type (medium) Rambouillet Ram. INFLUENCE OF AGE. TYPE AND FERTILITY IN RAMBOUILLET EWES 9 Breeding System As it was desired to produce an intermediate type, there was a slight deviation from random matings with reference to type. A significant nega- tive correlation (—.123) between sire and dam was found. This negative correlation shows that there were slightly more matings of unlike types than would have occurred by random matings. Methods of Sampling All wool samples were taken from three parts of the body, i. e., shoulder, side and thigh, immediately preceding the regular" spring shearing. The shoulder samples were consistently taken from a point approximately 3 inches back of the shoulder joint, the side samples midway between the shoulder and hip bone or at a point approximately over the tips of the last two ribs, and the thigh samples at approximately 3 inches below the hip joint. In certain instances with relatively heavy folded B type animals it was necessary to deviate from the plan slightly so as to avoid taking wool samples from prominent skin folds. At the time of obtaining the wool samples for diameter determinations they were properly identified and forwarded to the Wool Research Labora- tory at College Station for measurement. Method of Measuring Staple Length Length of staple was measured and recorded to the nearest one-eighth inch immediately before shearing at the same time the wool samples were taken for diameter measurements. These length measurements were de- termined on an unstretched fiber basis. Hultz (12) has reported that staple length averaged 66.54 per cent of the stretched fiber lengths. A thin measuring rule was inserted gently to the skin at several points on the respective body regions sampled (shoulder, side, and thigh) and an average of three readings from each of these regions was recorded. Owing to the even structure of the fiber tips of the Rambouillets used in this study the length of staple measurement is believed to be adequate for the purpose. All staple length measurements were adjusted to the equivalent of 365 days growth. Method of Measuring Diameter of Fiber The Brown and Sharpe micrometer caliper graduated to one-ten thou- sandth of an inch and which has been described by Hill (11) in 1921, Burns and Kohler (5) in 1925, and again by Burns (6) .in 1935, was used ‘to determine diameter of fiber measurements during the course of this study“. Precautions were taken to keep the calipers in as near perfect condition as possible. They were frequently returned to the factory for checking, clean- ing and-adjustment. Several calipers were retained for use over most of “Averages obtained in this report were converted to microns. 10 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION the period covered by this study and the instruments were checked with one another at frequent intervals throughout the entire period. All measure- ‘i ments of fibers during the course of this investigation were made by two laboratory technicians, a factor which undoubtedly contributed to the ac- curacy of this phase of the work. Diameter measurements were taken at I a point approximately one inch from the flesh or sheared end of the fiber. a One hundred fibers from each of the samples were measured immediately . after they were thoroughly cleansed with a solvent. Benzine was used ‘ during the early stage, but later carbon tetrachloride replaced benzine ‘ as a cleansing agent. Wool samples were kept in small envelopes which i in turn were enclosed in a larger envelope with flap. Laboratory tests ‘I failed to reveal any significant differences in diameter measurements of : the same fibers under the slightly varying laboratory conditions. Although A shoulder, side and thigh samples were taken throughout the period of A the entire experiment, diameter measurements of side and thigh samples , were not measured after 1932. The averages obtained for diameter of 7 shoulder samples are therefore not comparable to those obtained for the g side and thigh samples. Methods of Scouring Individual Fleeces At the time of shearing, fleeces to be scoured individually were placed . in bags each containing only one fieece, and a label showing ear tag num- ber, grease fleece weight, sex of animal, and date of shearing was attached. A After delivery to the Wool Research Scouring Laboratory at College. Station the individual fleeces were weighed to the nearest 0.1 "pound and] graded immediately preceding scouring. The emulsion scouring operation“. was done in a small three-bowl commercial scouring machine. In the earlier 5 stages of the experiment the single fleeces were not put through the dryer Q but were placed in containers and exposed to the sunlight to dry. However, a as the number of fleeces in the test increased it became impractical to A continue drying them by such a method. Accordingly, after determining I that it was possible to put single fleeces through the dryer without a. significant loss of scoured wool, such a procedure was followed. The temperature of the dryer was maintained at approximately 180 degrees Fahrenheit. After the scoured dried fleeces had been exposed to the at- mosphere in the wool scouring laboratory for a period of at least 24 hours A the scoured weights were recorded. Numerous preliminary tests including a Weighing on three successive days after scouring definitely showed that such a period is adequate for the normal regain of moisture of scouredl fleeces exposed to the relatively constant atmospheric conditions whicht prevailed in the wool scouring laboratory. All shrinkages were recorded f on the basis of both grease and scoured weights at the wool scouring ‘ laboratory. The scouring agents consisted of a neutral soap, soda ash, and water A heated to the usual temperatures used in commercial scouring of fine wools.3 Small scoured samples from each fleece were used in an extraction test ’ for the purpose of determining the percentage of grease remaining in 5 INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 11 the scoured wool. The amount of grease remaining in the scoured samples ranged consistently between 0.25 and 0.75 per cent, the average being closer t0 the latter. Statistical Treatment of Data Analysis 0f variance was made to determine the effects of age, type, and fertility 0n the various fleece characteristics studied. The number of individuals in the different sub-classes were unequal and therefore the data were analyzed by the method of expected numbers in the sub-classes, as reported by Snedecor and Cox (24). The error term used to test the significance of the mean differences was the pooled year, age, type, fertility sub-class variance. In all cases where mean differences or sources of variations Were des- ignated as significant, the t or F tests were on or below the .01 level. The averages given in Tables 1 to 9 inclusive are based on actual num- bers in the sub-classes. The summary Tables 10 and 11 show averages- based on expected sub-class numbers. These averages differ but slightly ~ from those which would have resulted had the actual numbers been used. RESULTS OF INVESTIGATIONS Influence of Age of Animal on Fleece WVeight The average fleece weights of unscoured and scoured wool for Ram- bouillet ewes in this study are shown for each age, 1 to 11 years inclusive, in Table 1. The heaviest production on the unscoured basis, B and C types averaged, was at 4 years, although the difference in weight between fleeces produced by 3 and 4 year old ewes respectively is not significant. On a scoured basis, fleece weights for the three-year old ewes averaged 0.03 pound heavier than for the four-year-old animals as is shown in Table 2. This slight difference is not significant. Spencer and coworkers (25) reported a study conducted at the United States Sheep Experiment Station at Dubois, Idaho, in which three-year-old Rambouillet ewes produced ap- proximately 0.5 pound more scoured wool per head than ewes of similar breeding one year older. In that study, however, the clean yields were based on the results of scouring a 250 gram (approximately 0.5 pound) sample taken from the side while in our experiment entire single fleeces were scoured separately. As shown in Tables 1 and 2, fleece weights produced by one-year-old ewes were significantly lower both on unscoured and scoured basis than at any of the subsequent ages through the eighth year. There was, how- ever, a gradual but steady decline in fleece with increasing age both on an unscoured and scoured basis after the ewes had reached the age of 4 years. The average annual decline in fleece weight between the ages of 4 and 8 years was approximately 0.3 pound unscoured and 0.13 pound. scoured basis. The production of wool, unscoured basis, by 6-year-old ewes in this study was approximately 0.5 pound less than that produced by 3-year-old ewes. Calculated on a percentage basis, the decline in fleece 12 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION Table 1. Relation of Age, Fertility, and Type to Unscoured Fleece Weight of Rambouillet Ewes, 1923-1940, inclusive _ Did Not Lamb During Lambed During Year Year All Records C Type B Type C Type B Type Age. in Years Ave. Ave. Ave. Ave. Ave. N0. lbs. No. lbs. N0. lbs. N0. lbs. No. lbs. . . . . . . . . . . . . . . . . . .. 682 7.72 72 9.04» 754 7.85 2 . . . . . . . . . . . . . . .. 340 8.93‘ 31 9.96 225 9.28 29 10.13 625 9.16 3 . . . . . . . . . . . . . . .. 342 9.12 41 9.56 107 9.84 19 11.51 509 9.40 4 . . . . . . . . . . . . . . .. 296 9.13 48 10.58 78 9.76 8 9.56 430 9.41 5 . . . . . . . . . . . . . . .. 243 8.85 43 10.06 60 9.47 6 12.08 352 9.16 6 . . . . . . . . . . . . . . .. 175 8.56 42 9.54 45 9.20 12 10.38 274 8.90 7 . . . . . . . . . . . . . . .. ‘125 8.26 35 9.52 39‘ 8.97 4 9.05 203 8.63 8 . . . . . . . . . . . . . . .. 83 7.94 22 8.46 36 8.63 5 9.10 146 8.23 9 . . . . . . . . . . . . . . .. 43 7.10 12 8.52 14 7.57 1 10.40 70 7.49 10 . . . . . . . . . . . . . . .. 16 6.85 4 7.70 8 7.24 2 10.20 30 7.29 11 . . . . . . . . . . . . . . .. 8 6.04 1 10.90 7 6.79 1 6.50 17 6.66 Totals** . . . . . . . . . . 1671 . . . . . . 279 . . . . . . 619 . . . . . . 87 . . . . . . 2656 . . . . . . Averages** . . . . . . . . . . . . .. 8.78 . . . . .. 9.69 . . . . .. 9.30 . . . . .. 10.40; . . . . .. 9.05 I *None bred to lamb at this age. _ _ _ **The records for the one year old ewes have not been included 1n these averages. Table 2. Relation of Age, Fertility, and Type to Clean Fleece Weight of Rambouillet Ewes, 1923-1940. inclusive ‘ ' Did Not Lamb During Lambed During Year Year _ All Records C Type B Type C Type l B Type Age in Years - Ave. Ave. Ave. Ave. Ave. No. lbs. No. lbs. No. lbs. No. lbs. No. lbs. 1* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 670 3.12 68 3.42 738 3.15 2 . . . . . . . . . . . . . . .. 340 3.67 31 3.78 223 3.81 29 3.77 623 3.74 3 . . . . . . . . . . . . . . .. 341 3.67 41 3.64 106 4.01‘ 19 4.37 507 3.77 4 . . . . . . . . . . . . . . .. 294 3.68 48 3.90 78 3.92 8 3.53 428 3.74 5 . . . . . . . . . . . . . . .. 243 3.55 43 3.51 59 3.95 6 4.17 351 3.62 6 . . . . . . . . . . . . . . .. 174 3.39 42 3.47 44 3.85 12 3.98 272 3.50 7 . . . . . . . . . . . . . . .. 125 3.22 35 3.49 37 3.58 4 2.92= 201 3.32 8 . . . . . . . . . . . . . . .. 82 3.14 22 3.03 34 3.48 a 3.34 143 3.21 9 . . . . . . . . . . . . . . .. 43 2.79 12 2.96 14 2.87 1 3.20 70 2.84 10 . . . . . . . . . . . . . . .. 16 2.58 4 2.82 7 2.83 2 4.00 29 2.77 11 . . . . . . . . . . . . . . .. 7 2.37 1 4.70 7 2.59 1 2.50 16 2.62 T0tals** . . . . . . . . . . 1665 . . . . . . 279 . . . . . . 609 . . . . . . 87 . . . . . . 2640 . . . . . . Averages** . . . . . . . . . . . . .. 3.52 . . . . . . 3.55 . . . . . . 3.79 . . . . . . 3.86; . . . . .. 3.60 *None bred to lamb at this age. _ _ **'I‘he records for the one year old ewes have not been included in these averages. *2 INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 13 weight unscoured basis between the ages of four and eight years was approximately 13 per cent. On a scoured basis the 12 month fleeces pro- ducedby ewes during the eighth year of age averaged about 15 per cent less than that yielded by 3-year-old ewes. On the basis of these data, when scoured 12 months French combing fine wool is selling at $1.00 per pound a 3-year-old ewe producing 3.77 pounds clean wool would return approximately $0.56 more annually from wool than an 8-year-old ewe which produced 3.21 pounds. Influence of Age of Animal on Length of Staple As shown in Table 3, the first fleece or that produced by ewes sheared at one year of age and converted to a 365-day growing period averaged 2.49 inches which is significantly greater in length than at any of the subsequent ages. The average fiber length produced by 2-year-old ewes was 2.39 inches, by 3-year-olds 2.31 inches, by 4-year-olds 2.28 inches, by 5-year-olds 2.22 inches, by 6-year-olds 2.18 inches, by 7-year-olds 2.09 inches, by 8-year-olds 2.05 inches. Between the ages of 1 and 6 years there was a decrease of approximately 0.3 inch or nearly 12 per cent in fiber length, an amount suflicient to place it in a shorter and less valuable length class. Between the ages of 1 and 8 years the average decrease in fiber length was 0.44 inch or about 18 per cent. Table 3. Relation of Age, Fertility, and Type to Staple Length of Rambouillet Ewes, 1923-1940, inclusive Did Not Lamb During Lambed During Year Year — All Records C Type B Type C Type B Type Age in Years Ave. Ave. Ave. Ave. ‘ Ave. No. inches No. inches No. inches No. inches No. inches 1* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 693 2.51 71 2.27 764 2.49 2 . . . . . . . . . . . . . . .. 338 2.39 31 2.14 211 2.46 29 2.14 609 2.39 3 . . . . . . . . . . . . . . .. 343 2 33 43 2.10 108 2.37 18 2.14 512 2.31 4 . . . . . . . . . . . . . . .. 296 2.30 46 2.10 79 2.35 8 1.-99 429 2.28 5 . . . . . . . . . . . . . . .. 244 2.23 42 2.00 59 2.35 i6 2.07 351 2.22 6 . . . . . . . . . . . . . . .. 171 2.18 42 1.99 46 2.33 11 2.15 270 2.18 7 . . . . . . . . . . . . . . .. 127 2 l0 36 1.96 38 2.23 5 1.76 206 2.09 8 . . . . . . . . . . . . . . .. 84 2 03 22 1.90 35 2.22 5 1.84 146 2.05 9 . . . . . . . . . . . . . . .. 42 1 91 12 1.77 14 1.94 1 1.90 69 1.89 10 . . . . . . . . . . . . . . .. 16 1.80 4 1.70 8 2.00‘ 2 1.90 30 1.85 ll . . . . . . . . . . . . . . .. 8 1.80 1 1.80 7 1.73 1 1.50 17 1.75 Totals** . . . . . . . . . . 1669 . . . . . . ‘ 279 . . . . . . 605 . . . . . . 86 . . . . . . 2639 . . . . . . Averages** . . . . . . . . . . . . .. 2.26 . . . . .. 2.02? . . . . .. 2.35‘ . . . . .. 2.07 . . . . .. 2.25 *None bred to lamb at this age. _** Fhe records for the one year old ewes have not been included in these averages. 14 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION Bell (2) and coworkers at the Ohio Station had previously reported that age of the animal does not influence total annual wool growth for Merinos. Influence 0f Age of Animal on Diameter of Fiber The diameter of fiber as determined by the measurement of samples of wool from shoulder, side, and thigh, respectively, averaged slightly but significantly finer for fleeces produced during the first age year than at any of the subsequent ages. As shown in Tables 4, 5, and 6, the diameter of shoulder, side and thigh samples based on 1277 observations averaged 13.6, 13.6 and 14.6 microns respectively. The average diameter of the thigh sample is significantly coarser than the shoulder or side. The same tables show, however, that the average diameter of fiber produced during the first age year averaged 11.8, 12.2 and 13.2 microns for shoulder, side and thigh respectively, or slightly but significantly finer than is pro- duced at any of the succeeding ages. A detailed examination cf Table 7 will reveal that after the first (or lamb) fleece, diameter of wool fiber remains relatively constant. These findings differ fromthose reported in 1935 from work at this station (15) covering diameter of mohair fiber which showed a pronounced tendency to become coarser as the age of Angora goat increased. Table 4. Relation of Age, Fertility, and Type to Diameter of Fiber at Shoulder of Rambouillet Ewes, 1923-1940, inclusive Did Not Lamb During Lambed During Year Year , 1 All Records C Type B Type ' C Type B Type Age in Years 1 —- Ave. Ave. Ave. Ave. 1‘ 1 Ave. No. microns N0. micrars No. micrai s No. 1111010151 No. ‘micmrs 1* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 701 11.7 75 12.81 7765 11.8 2 . . . . . . . . . . . . . . .. 342 13.1 31 14 6 220 12.9 29 14.61 622 13.2 3 . . . . . . . . . . . . . . .. 351 13 1 43 14 7 109 13.0 18 13.7: 521 13.2 4 . . . . . . . . . . . . . . .. 298 13 6 48 14 7 79 13.3 8 13.75 433‘ 13.6 5 . . . . . . . . . . . . . . .. 244 13.3 44 15 1 59 13.0 6 14.61 353 13.5 6 . . . . . . . . . . . . . . .. 175 13.2 4-2 14 4 46 13.5 10 15.1: 273 13.5 7 . . . . . . . . . . . . . . .. 127 13.4 36 14.4 38 13.1 5 16.3} 206 13.6 8 . . . . . . . . . . . . . . .. 84 13.8 22 144 34 12.7 5 11.91 11> 13.6 9 . . . . . . . . . . . . . . .. 41 12.3 12 14 4 15 13.5 1 11.23 69 12.9 10 . . . . . . . . . . . . . . .. 16 13.8 4 13 o 10.9 2 12 s}, so 12.9 11 . . . . . . . . . . . . . . .. 8 13.5 1 16 5 7 14 O 1 14 23 17 13.9 Totals** . . . . . . . . . . 1686 . . . . . . 283 . . . . . . 615 . . . . . . 85 . . . . . .1 2669 . . . . .. 1 Averages** . . . . . . . . . . . . .. 13.3 . . . . .. 14.6 . . . . .. 13.0 . . . . .. 14.2; . . . . .. 13.4 Number and Average of all Records for the Period 1923-32, Inclusive. . . . . . . . 12773 l5- 6 *None bred to lamb at this age. . **The records for the one year old ewes have not been included in these averages. Table 5. Ewes, 1923-1932, inclusive INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 15 Relation of Age, Fertility, and Type to Diameter of Fiber at Side of Rambouillet Age in Years 'l‘otals**.......... Averages** . . . . . . - - ' Did Not Lamb During Lambed During Year Year C Type —WB Type C Type B Type ~An Records N0. No mpiggi s No. mliciifihs No. N0. . . . . . . . . . . . . . . . . . . . . . . .. 320 15.1 59 13.0 379 12.2 166 13.5 25 14.9 95 13.3 22 14.8 308 13.6 185 13.0 34 14.7 53 12.5 11 13.9 283 13.2 135 13.8 36 14.9 42 13.3 6 13.6 219 13.9 96 13.7 34 15.1 21 13.4 4 15.2 155 14.0 63 13.4 28 14.1 17 13.8 6 14.3 114 13.7 48 13.4 26 14.4 16 12.4 2 16.4 92 13.5 37 13.8 13 13.2 10 12.9 3 13.1 63 13.5 11 12.6 8 13.9 6 11.9 12.9 26 12.9 3 14.4 4 11.8 1 12.7 2 12.6 1O 12.8 2 11.8 1 13.7 3 13.0 1 12.2 7 12.7 746 . . . . . . I 209 . . . . . . 264 . . . . . . 58 . . . . . . 1277 . . . . . . . . . . .. 1341......‘ 145...... 13.1...... 14.3...... 13.6 *None bred to lamb at this age. _ _ **The records of the one year old ewes have not been included 1n these averages. Ewes, 1923-1 932, inclusive Table 6. Relation of Age. Fertility, and Type to Diameter of Fiber at Thigh of Rambouillet i Did Not Lamb During Lambed During Year Year i All Records ‘j C Type B Type C Type B ‘Type Age in Years i Ave. Ave. Ave. Ave. Ave. No. micrars No micrars No. microns No. micrors No. microns 1* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 320 13.1 59 13.9 379 13.2 2 . . . . . . . . . . . . . . .. 166 14.3 25 15.8 95 14.1 22 15.9 308 14.5 F 3 . . . . . . . . . . . . . . .. 185 13.9 34 15.7 53 13.5 11 15.0 283 14.1 4 . . . . . . . . . . . . . . .. 135 14.9 36 16.0 42 14.3 >6 14.1 219 14.9 5 . . . . . . . . . . . . . . .. 96 15.0 34‘ 16.4 21 14.2 4 15.9 155 15.2 6 . . . . . . . . . . . . . . .. 63 14.6 28 15.4 17 14.7 6 15.5 114 14.9 7 . . . . . . . . . . . . . . .. 48 14.6 26 16.1 16 13.4 2 17.3 92 14.9 8 . . . . . . . . . . . . . . .. 37 15.2 13 13.7 10 14.0 3 13.5 63 14.7 9 . . . . . . . . . . . . . . .. 11 14.2 16.0 6 13.5 1 13.9 26 14.6 10 . . . . . . . . . . . . . . .. 3 15.2 13.2 1 11.2 2 14.0 10 13.7 11 . . . . . . . . . . . . . . .. 2 13.1 1 15.0 3 14.7 1 14.0 7 14.1 Totals** . . . . . . . . . . 746 . . . . . . 209 . . . . . . 264 . . . . . . 58 . . . . . . 1277 . . . . . . Averages** . . . . . . . . . . . . .. 14.5 . . . . .. 15.7 . . . . .. 14.0 . . . . .. 15.3 . . . . .. 14.6 *None bred to lamb at this age. **The records 0f the one year old ewes have not been included inithese averages. 16 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION Influence of Age of Animal on Body Weight The average Weights of the ewes by ages shortly after shearing are shown in Table 8. The data show that the Rambouillet ewes used in these studies continued to increase in body weight to and including the sixth year of age. The average Weight of 766 sheared yearling ewes was 82 pounds. Six hundred twenty-seven 2-year-old ewes averaged 98 pounds, five hundred twenty-two 3-year-old ewes averaged 107 pounds, four hun- dred thirty-one 4-year-old ewes averaged 111 pounds, the maximum weight being reached at 5 and 6 years of age when body weights averaged 114 ‘pounds. After ewes had reached the age of 6 years there was a tendency toward a slight but steady decline in bcdy weight. The Rambouillet ewes used in this study averaged, as yearlings, 16 per cent less in weight than 2-year-olds, 23 per cent less than 3-year-olds, and 26 per cent less than 4-year-olds. Influence of Staple Length on Diameter of Fiber The longer staple fleeces produced by Rambouillet ewes tended to be very slightly finer in diameter as shown in_Table 12. The correlation of length of fiber and diameter for all ages combined was only —.19, but Table 7. Relation of Age and Type of Animal to Diameter* of Fiber at Shoulder, Side and Thigh of Rarnbouillet Ewes Shoulder Side Thigh (1923-40) (1923-32) (1923-32) Age in i Years C Type B Type C Type B Type C Type j B Type 1 Average . . . . . . . . . . . . . . .. 11.7 12.8 12.1 13.0 13.1 i 13.9 Number . . . . . . . . . . . . . . . . 701 75 320 59 320 50 2 Average . . . . . . . . . . . . . . .. 13.0 14.6 13.4 14.8 14.2 15.8 Number . . . . . . . . . . . . . . . . 562 6O 261 47 261 47 3 Average . . . . . . . . . . . . . . .. 13.1 14.4 12.9 14.5 13.8 Number . . . . . . . . . . . . . . . . 460 61 238 45 238 45 4 Average . . . . . . . . . . . . . . .. 13.5 14.5 13.7 14.7 14.7 15.7 Number . . . . . . . . . . . . . . . . 377 56 177 42 177 42 5 Average . . . . . . . . . . . . . . .. 13.2 15.1 13.7 15.1 14.8 16.4 Number . . . . . . . . . .' . . . . . . 303 50 117 38 117 38 6 Average . . . . . . . . . . . . . . .. 13.3 14.5 13.5 14.1 14.6 15.4 Number . . . . . . . . . . . . . . . . 221 52 80 34 80 34 7 Average....'. . . . . . . . . . .. 13.3 14.6 13.1 14.5 14.3‘ 16.2 Number . . . . . . . . . . . . . . . . 165 41 64 28 64 28 8 Average . . . . . . . . . . . . . . .. 13.5 14.0 13.6 13.2 15.0 13.7 Number . . . . . . . . . . . . . . . . 118 27 47 16 47 16 9 Average . . . . . . . . . . . . . . .. 12.6 14.2 12.4 13.9 13.9 16.0 Number . . . . . . . . . . . . . . .. 56 13 17 8 17 8 1O Average . . . . . . . . . . . . .. 12.8 13.0 14.0 12.1 14.2 13.4 Number . . . . . . . . . . . . . . .. 24 6 4 6 4 6 11 Average . . . . . . . . . . . . . . .. 13.7 15.4 12.5 13.0 14.0 11.5 Number . . . . . . . . . . . . . . .. 15 2 5 2 5 2 *Microns. “- INFLUENCE OF AGE, TYPEI AND FERTILITY IN RAMBOUILLET EWES 17 was ‘significant. Spencer and associates (25) in 1928, reported that fine- ness of wool fiber in Rambouillets was practically unassociated with length of staple giving a coeflicient of correlation of —.04. In their study as in ours there was an important relationship between length of staple and clean fleece weight. Clean fleece weight tended to increase with length of staple. Influence of Fertility 0n Fleece Weight and Shrinkage v Unscoured and scoured fleece weight data both for fertile and non- ilambing ewes were analyzed in this study. Ewes that did not produce lambs at the several ages yielded fleeces that weighed slightly but signifi- cantly heavier than those produced by ewes of comparable age which pro- duced lambs. Reference to Table 1 reveals that on an unscoured basis 225 fleeces produced by 2-year-old C type ewes which did not lamb averaged 0.35 pound more unscoured wool per head than 340 ewes of the same age that produced lambs. One hundred seven unscoured fleeces from 3-year-old non-lambing C type ewes averaged 0.72 pound more than those produced by ewes of the same age producing lambs. Seventy-eight unscoured fleeces ,from 4-year-old non-lambing C type ewes averaged 0.63 pound more than 296 fleeces from 4-year-old ewes which produced lambs. As shown in Table 2, two hundred twenty-three fleeces produced by 2-year-old non- ~_ Table 8. Relation of Age, Fertility and Type to Body Weight of Rambouillet Ewes, - 1923-1940, inclusive Did Not Lamb During Lambed During Year Year C Type B Type C Type B Type Ave. l Ave. Ave. Ave. Ave. N0. lbs. No. lbs. Ave. lbs. No. lbs. No. lbs. All Records Age in Years y 1* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 595 81 71 85 755 82 2 . . . . . . . . . . . . . . .. 842 95 29 95 227 101 29 95 527 98 ' 8 . . . . . . . . . . . . . . .. 858 104 48 105 107 115 19 117 522 107 1 4 . . . . . . . . . . . . . . .. 298 109 48 111 77 120 8 114 481 111 1 5 . . . . . . . . . . . . . . .. 245 112 44 110 50 122 7 115 855 114 j 5 . . . . . . . . . . . . . . .. 177 112 41 114 47 118 12 121 277 114 5 7 . . . . . . . . . . . . . . .. 127 111 85 114 88 114 5 118 205 112 J 8 . . . . . . . . . . . . . . .. 88 110 22 108 35 115 5 119 145 112 ~19 . . . . . . . . . . . . . . .. 48 105 12 112 15 114 1 95 71 109 A10 . . . . . . . . . . . . . . .. 15 117 4 109 8 105 2 117 so 118 ‘11 . . . . . . . . . . . . . . .. 8 105 . . . . . . . . . . .. 5 109 1 88 15 105 "Tbtfls** . . . . . . . . .. 1584 . . . . .. 279...... 515 . . . . .. A 88 . . . . .. 2555 . . . . .. ;Avmages** , . . . . . . . . . . . .. 105 . . . . .. 109 . . . . .. 114 . . . . .. 110 . . . . .. 108 *None bred to lamb at this age. _ **The records of the one and eleven year old ewes have not been included 1n these averages. 18 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION lambing C type ewes averaged 0.14 pound more clean wool than 2-year-old ewes of the same type which produced lambs; 3-year-old non-lambing ewes produced 0.34 pound more than 3-year-old fertile ewes; 4-year-old non-lambing ewes produced 0.24 pound more per head than the 4-year-oldl fertile ewes; 5-year-old non-lambing ewes produced 0.4 pound more per head than 5-year-old fertile ewes; and 6-year-old non-lambing C type ewes averaged 0.46 pound more scoured wool than was produced by 6- year-old fertile ewes. _ There were, as shown in Table 9, no significant differences in wool shrinkages from scouring within the respective C and B types of the fertile and non-lambing ewes. The shrinkage of 340 fleeces produced by 2-year-old C type ewes that lambed averaged 58.6 per cent as compared with 58.8 per cent for fleeces from 223 non-lambing ewes of similar age and type. Shrinkage for 341 fleeces from fertile 3-year-old C type ewes was 59.4 per cent as compared with 59.1 per cent for 106 fleeces produced - by non-lambing C type ewes. Two hundred ninety-four fleeces from 4- year-old C type fertile ewes showed an average shrinkage of 59.4 per cent as compared with 59.7 per cent shrinkage of fleeces from '78 non- lambing 4-year-old C type ewes. l Fertility, as shown in Table 10, exerted some influence on unscoured" fleece weight since the non-lambing ewes averaged 9.47 pounds as compared with 8.90 pounds for ewes that lambed during the year or a difference of Table 9. Relation of Age, Fertility and Type to Shrinkage Percent 0f Fleeces of Rambouilletl Ewes, 1923-1940, inclusive Did Not Lamb During Lambed During Year Year All Records C Type B Type C Type B Type Age in Years Ave. Ave. Ave. Ave. Ave. No. % No. % No. % No. ‘7, _ No. °7¢ 1* . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . 670 59.3 68 62.1 738 59.5 . 2 . . . . . . . . . . . . . . . . 340 58.6 31 62 .1 223 58.8 29 62 .4 623 59.0‘ 3 . . . . . . . . . . . . . . .. 341 59.4 41 61.6 106 59.1 19 61.7 507 59.6 4 . . . . . . . . . . . . . . . . 294 59.4 48 62.8 78 59 7 8 62.5 428 59.9 5 . . . . . . . . . . . . . . . . 243 59.7 43 64.7 59 57 8 6 64.8 351 60.1 6 . . . . . . . . . . . . . . .. 174 60.1 42 63.3 44 58 1 12 61.7 272 60.3 7 . . . . . . . . . . . . . . .. 125 61.0 35 63.4 37 59.6 4 68.0 201 61.3‘ 8 . . . . . . . . . . . . . . .. 82 60.2 22 63.9 34 59.1 5 63.8 143 60.6 9 . . . . . . . . . . . . . . .. 43 60.6. 12 65 1 14 61 9 1 69.0 70 61.7 10 . . . . . . . . . . . . . . .. 16 62.1 4 63 8 7 60.9 2 61 0 29 62.0 11 . . . . . . . . . . . . . . .. 7 61.4 1 57 0 7 60 9 1 61 0 16 60.9 Totals** . . . . . . . . . . 1665 . . . . . . 279 . . . . . . 609 . . . . . . 87 . . . . . . 2640 . . . . .. Avcrages** . . . . . . . . . . . . .. 59.6 . . . . .. 63.2 . . . . 0'1 59.0 . . . . .. 62.71 . . . . . 59.9 *None bred to lamb at this age. _ _ **The records of the one year old ewes have not been included 111 these ‘averages. 19 INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES Table 10. Summary Showing the Efiect of Fertility on Certain Fleece Characters and Body Weigh?“ I Lambed Did Not Lamb During Year During Year Mean N0. ~ . No. Difference Records Average Records Average __ Fleece Weight (Unsecured) . . .. . . . 1950 8.90 706 9.47 0.57** Fleece \\"eight (Scoured). . . . . . . . 1944 3.54 696 3.81 ()_.27** ' Shrinkage Percent . . . . . . . . . . . . . . 1944 60.03 696 59.52 0.51 ** Staple Length (Inches). . .. . . . . . . 1948 2.23 691 2.31 0.08** Fiber Diameter at Shoulder j V (Microns) . . . . . . . . . . . . . . . . . . 1969 j 13.5 700 13.2 O.30** ' Animal Weight (Pounds) . . . . . . .. 1963 i 105.9 703 113.5 7T6 ** *The records of the one year olds have not been included in these averages. **i\'leans significant on .01 level. 0.57 pound in favor of the dry ewe. Scoured fleece weight produced by the non-lambing ewes averaged 0.27 pound heavier than those produced by the fertile ewes. Workers at the Ohio Station (2), in 1936, reported that pregnancy alone does not influence the rate of wool growth by well fed Merino sheep, how- ever, parturition and the starting of the milk flow exerted a retarding influence on growth of the wool fiber. In this study, during the lambing period ewes with lambs were in most instances confined in dry lot at headquarters for a relatively short period. It is believed that as a result of this management ewes showing a tendency toward openness of fleece may have accumulated slightly more foreign matter in the wool which-probably increased shrinkage. Influence of Fertility on Staple Length There was very slight advantage in length of fiber in fleeces produced by the ewes which failed to produce lambs at any of the respective ages over those which had currently lambed. As shown in Table 3, the 211 fleeces produced by C type non-lambing 2-year-old ewes showed an average fiber length of 2.46 inches while fleeces from 338 fertile C type ewes of the same age produced 2.39 inches of fiber or 0.07 inch less than the non- lambing ewes. A comparison of the fiber length of the fertile and non- R lambing C type ewes revealed an advantage of 0.04 inch and 0.05 inch in .. w)" " favor of the non-lambing ewes at 3 and 4 years respectively. A study of I Table 3 reveals however that the differences in fiber length in favor of the non-lambing C type ewes becomes more pronounced between the ages of 4 and 8 years. Influence 0f Fertility on Fineness of Fiber The diameter of fiber produced by pregnant ewes was slightly coarser on the average than that produced by non-lambing ewes in the same age 20 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION groups. Bosman (3) has reported that pregnancy does not influence I Merino W001 fineness, however a finer quality fiber is produced during the suckling or lactation period. In our study diameter measurements were those covering fiber growth during pregnancy or before lambing. No prac- tical importance is attached to the very slight but significant diflerence in fineness between the fertile and non-lambing groups as shown in Table 4. A possible explanation of the fact that fertile ewes produced a slightly coarser fiber than the non-lambing ewes is that the fertile ewes received a more liberal feed supplement than did the dry ewes. Wilson (26), in 1931, reported that wool produced by sheep on sub- a maintenance ration showed slower growth, a finer fiber diameter or thick- ~ ness, and lighter‘ clean weight fleece than is produced by comparable ani- A mals full fed on a balanced ration. Maré and Bosman (20) (1934), at the , conclusion of a study of the effect cf the plane of nutrition on the Merino, 1 reported that this factor is of great significance to the Merino stud breeder. 1 It was shown in their study that quantity and quality in a Merino fleece ‘j are influenced by the nutrition of the animal. Under-feeding for 18 months ‘ reduced the scoured fleece weights from 5.55 pounds to 4.21 pounds while fiber fineness was reduced from 17.9 microns at the beginning -of the » test to 14.3 microns at the end of the period. The study further showed A that fiber diameter was restored to normal under adequate nutrition. Influence of Fertility on Body Weight The C type fertile 2-year-old ewes, as shown in Table 8, shortly after i shearing averaged 95 pounds per head or 6 pounds less than non-lambing ewes; 3-year-old fertile ewes under similar conditions averaged 104 pounds ; or 12 pounds lighter than 3-year-old non-lambing C type ewes; 4-year-old : C type fertile ewes averaged 109 pounds or 11 pounds lighter than non- p lambing C type ewes of the same age; while 5-year-old ewes of similar - type averaged 112 pounds or 10 pounds less than non-lambing ewes. Non- p lambing 2-year-old C type ewes averaged 21 pounds or 17 per cent less, r than 5-year-old non-lambing ewes of similar type, while fertile Z-year-old C type ewes weighed 17 pounds or 15 per cent less than fertile 5-year-old " ewes of similar type. These difierences in body weight between the re- I spective age groups are believed to be due largely to condition of fleshing. f; Influence of Body Type on Fleece Weight and Shrinkage Texas Station workers were among the first in this country to recognize * the relationship of body type to wool production in Rambouillet sheep. I Not until this study had been underway for several years was it rather * definitely indicated and reported (14) (16) that in the same flock C type V» Rambouillet ewes produced fleeces which on a scoured basis yielded ap- proximately as much clean wool per head as ewes with heavy skin fold development. The average unscoured fleece weight of 279 fleeces from B type ewes, that currently dropped lambs, as shown incTable 1, was 9.69 pounds or' w“ INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 21 0.91 pound heavier than 1671 unscoured fleeces produced currently by C type fertile ewes. Also in the same table it is shown that among ewes which did not lamb 87 fleeces produced by B type ewes averaged 10.40 ? pounds as compared with 9.30 pounds for 619 unscoured fleeces produced by C type ewes that did not lamb, or a difference of 1.10 pounds in favor I of the B type ewes insofar as unscoured fleece Weight is concerned. On A a scoured basis, however, as shown in Table 2, the one pound difference favoring the B type ewes practically disappeared. Average clean weight a of 1665 fleeces produced by C type ewes that lambed during the year was a 3.52 pounds as compared with an average weight of 3.55 pounds clean 1 basis for 279 fleeces produced by B type ewes which had currently pro- i duced lambs. Also the average clean weight of 609 fleeces produced by C L type ewes which did not currently produce lambs was 3.79 pounds as com- pared with 3.86 pounds for 87 fleeces produced by B type ewes that did not lamb. As shown in Table 9, the average shrinkage of 279 fleeces produced by 5 B type fertile ewes was 63.2 per cent as compared to 59.6 per cent for l 1665 fleeces produced by C type fertile ewes. Among the groups which I did not lamb currently 87 fleeces produced by B type ewes showed an average shrinkage of 62.7 per cent as compared with 59.0 per cent for f 609 fleeces produced by C type ewes which did not lamb currently. I It is observed that in each instance the fleeces produced by B type T Rambouillet ewes shrank significantly greater than those produced by C if type ewes. In a comparison of the fleeces produced by the non-lambing ewes as is also shown in Table 9 those from the B type ewes shrank 3.7 points V, more than the fleeces from the C type ewes; also in the comparison be- lgtween the B and C type fertile ewes the fleeces from the B type ewes shrank 3.6 points more than did the fleeces produced by the C type gewes. _ l; Nordby (22) has recently reported a significant difference in shrinkage 'l(0f wools *2 inches and 3.4 inches in length produced by yearling Ram- ‘lbouillet ewes. In his study the shorter fibered fleeces shrank 63 per cent 5 as compared with an average of 55 per cent for the longer staple fleeces. A Spencer and coworkers (25) have also reported that the weight of ctual clean wool in the fleece is only very slightly affected by neck folds. In their study smooth-necked Rambouillet ewes produced fleeces that were reer from heavy weights of grease and dirt, longer in staple, slightly finer, of a little higher character and less dense than the fleeces from rythe more wrinkled ewes. The average clean fleece weights of the C type and of the B type ewes, as shown in Table 11, did not differ significantly. It is generally true that fleece shrinkages will vary widely depending ‘upon type of sheep and kind of range upon which they are grazed. It jnay be safely predicted however that the fleeces produced by the heavier Lkin folded type will usually shrink several points more than-fleeces pro- f; by smooth-bodied animals of similar breeding under similar grazing " 7nditions. 22 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION Table ll. Summary of All B Type with All C Type Rambouillet Ewes in These Experiments C Type B 'l‘ype ’ " ‘ Mean No. N0. Difference Records Average Records Average l Fleece Weight (Unscoured) . . . . . . 2290 8.91 366 9.93 l.02** Fleece Weight (Scoured) . . . . . . .. 2274 3.60 see 3.66 0.06 Shrinkage Percent - _ - - - - - - . . . . . . 2274 59.41 366 62.93 3.52** Staple Length (Inches) . . .. . . . _ . . 2274 2.28 365 2.05 I 0.23** Fiber Diameter at Shoulder t (Microns) . . . . . . . . . . . . . . . . .. 2301 13.2 368 14.5 Z 1.30** l Animal Weight (Pounds) . . . . . . .. 2299 107.9 367 107.9 ‘ 0.00 **Means significant on .01 level. An increased length of staple (within breeds) is quite generally asso- ciated with a direct increase in clean fleece weight. However, the fleeces from the C type ewes in this study, which were significantly longer in staple than those from the B type ewes, yielded clean wool of the same average weight rather than greater. On the other hand, when staple length was correlated with clean fleece weights of individual ewes of the same age, both types included, there was a significant correlation at each age. This showed that increased staple length resulted in a very definite increase in clean weight of wool. These findings are in agreement with those of Pohle and Keller (23) (1943), who have reported that staple length has . a great influence on clean fleece weight. Influence 0f Body Type on Staple Length As shown in Table 3, C type Rambouillet ewes consistently produced a longer wool staple than did the B type ewes of similar ages. Also as is shown in Table 11, the fiber length of 2274 fleeces produced by C type ewes averaged 2.28 inches as compared with an average staple length of 2.05 inches for 365 fleeces produced by B type ewes. A number of fleeces produced by the C type ewes were classified as strictly combing, being 2.5 inches or more in staple length. Spencer (25) and coworkers reported in1928 that freedom from body‘ folds was correlated with increased length of staple, slightly finer fibers and a very slight reduction in scoured fleece weight. Influence of Body Type on Diameter of Fiber The diameter of wool fiber produced by C type ewes was significantly finer than wool produced by B type ewes of corresponding ages. It has been observed that coarser fibers are produced on the crest of skin folds or wrinklesthan on unwrinkled portions of the body, which may be one of the factors that accounts for the difference in fiber diameter laetxveen B and C type Rambouillet ewes. “Wwvxwwyjwvv-v": ~1 n" i ~+ur~=~1 www ‘ \ INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 23 As shown in Table 4, fiber diameter of 1686 shoulder samples from fertile C type ewes averaged 13.3 microns as compared with an average of 14.6 microns for shoulder samples from 283 fleeces produced by fertile B type ewes. Diameter of 746 side samples produced by fertile C type ewes, as shown in Table 5, averaged 13.4 microns as compared with an average of 14.5 microns for side samples from 209 fleeces produced by fertile B type ewes. Also as is shown in Table 6, the fiber diameter of 746 thigh samples from fertile C type ewes averaged 14.5 microns as compared with an average of 15.7 microns for thigh samples from 209 fleeces produced by fertile B type Rambouillet ewes. As is clearly shown in Table 7, the diameters of wool fibers from shoulder, side and thigh areas respectively are finest during the first year’s production. Fiber diameter at all subsequent ages to and including the 9th year of age, although slightly but significantly coarser than the first year’s production, show relatively small variation in diameter from one age to another after the first or yearling age. Influence of Type on Body Weight As has been stated previously in this bulletin, “off type” or undesirable animals were removed from thefiock either at the weaning age or as yearlings. The average weights of the C and B type ewes are shown by ages in Table 8. There was an increase in body weight for both B and C type ewes until the fifth or sixth year after which there was a tendency toward a gradual decline. At one year of age 695 C type females averaged 81 pounds as compared with an average weight of 85 pounds for 71 B type females. There was a gradual increase in weight to 112 pounds for fertile B type ewes. At 6 years of age 47 C type non-lambing ewes averaged 118 pounds as compared to a 121 pound average of 12 non-lamb- ing B type ewes of similar ‘age. Under conditions of inadequate nutrition during extended periods, how- T ever, body weight is reduced. Mare and Bosman (20), in 1934, reported that during a nine months’ period of under-feeding body weights of- Merino sheep were reduced approximately 16 per cent, whereas on a full ration a gain of approximately 11 per cent over initial weights resulted. Influence of Type of Rambouillet Rams on Fleece Weight, Shrinkage, Staple Length, and Diameter of Fiber During the course of this study records of fleeces produced by Ram- bouillet rams, including stud and range animals, were kept. Unscoured fleece weights produced by a representative number of rams at each age through and including the fourth year consistently showed that the B type rams had an advantage over the C type rams of approximately one pound at each age. The shrinkage of 460 fleeces produced by C type rams averaged 62.8 per cent as compared with 64.6 per cent for 130 fleeces produced by B type 177 fertile 6-year-old C type ewes as compared with 114 pounds for 41- Registered Range Rambouillet Ewes Used in This Study Table 12. Coefficients of Correlations of Certain of the Fleece Characters in Wool Production at the Different Ages of Age in Years Total Characters Correlated 1 2 3 4 5 6 7 8 9~12 2-12 1-12 Fleece weight: Clean weight. . . .. . .. .93** .76** .78** .78** .73** .77** .84** .83** .84** .80** .84** Shrinkage % . . . . . .. .35** .41** .40** .42** .41** .46** .20** .24** .32** .34** .34** Staple length . . . . . .. .35** .14** .17** .l5** .10 .14* .23** .26** .36** .24** .l5** Diameter tiber . . . . .. .25** .08 —.02 .03 —.02 .00 .01 .10 .07 .03 .16** Body weight. . . .. . .. .53** .37** .34** .30** .28* .21** .26** .46** .43** .26** .41** Clean weight: Shrinkage % . . . . . .. .l0* ~—.25** ——.25** —.22** ——.3l** ~e.20** .32** .33** —.23* —.28** ~.23** Staple length . . . . . .. .54** .49** .4s** .47** .4s** .49** .51** .58** .ts0** .56** .42** Diameter fiber... . . . .09* .l5** .04 .09 —. 10 .05 .05 .01 —.05 .04 .13** Body weight. . _ .. . .. .54** .37*3‘ .42** .34** .40** .27** .34** .40** .46** .26** .4l** Shrinkage %: Staple length . . . . . .. .s5** g-.42** .43“ -.44** -.4s** ~.51** .54** .5s** -.45** -.4s** -.44** Diameter 1iber...... .12** ~.l0* ~——.09* —.08 .10 ~09 .06 .17* .25* —.0l .02 Body weight . . . . . . . .05 .05 .07 —.02 —.0l ~.05 .13 .09 —.03 .02 .05 Staple length: Diameter fiber . . . . .- 11* “.04 —.1l* —.04 ——.12* —.05 .23** .24** ——.29** —.11** —.19** Body Weight..... 15** .08 .12** .04 .l8** .08 .08 .07 25* —.02 —.18** Diameter fiber: Body weight........ .25** —.0l} .06 —~ 08 —.l5** .08 .01 .04 .14 .02 .23** Number . . . . . . . . . . . . . . . . 722 585 495 420 345 262 197 138 112 2554 3276 *Signifieant on .05 level. “Significant on .01 level. f/Z NOILVLS LNEIWIHSIcIXH TVHQJIIIIOIHSV SVXELL ‘L29 'OI\I NLLEUYIIISI INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 25 rams. Diiferences in fleece weights between types disappeared in scouring. A Staple length of 741 fleeces produced by C type rams averaged 2.42 inches as compared with a length of 2.25 inches for 172 fleeces from B 7 type rams or an advantage of 0.17 inch in favor of the smooth-bodied type. With respect to body weight animals of each type averaged approximately if the same at each of the several ages. i‘ Diameter of wool fibers from 551 shoulder samples from'C type Ram- fbouillet rams at one year averaged 11.7 microns as compared with an average of 12.4 for fibers from 97 shoulder samples from B "type one iyear old Rambouillet rams. These findings are in similar order to fiber 3 diameter measurements taken from the shoulder area on C and B type Rambouillet ewes. Correlation of Certain Fleece Characters at the Dilferent Ages v_ The coeflicients of correlation of unscoured fleece weight, clean fleece fiweight, shrinkage of fleece, staple length and diameter of wool fiber of {all ewes at the different ages, with each other are shown in Table 12. fThe correlation coeflicients between unscoured and scoured fleece weights fat all ages were relatively high‘. The correlation between unscoured "gfleece weight and staple length was highly significant even though rather {low} That between unscoured fleece weight and body weight was slightly Qhighei- and was highly significant. The correlation of clean fleece weight and body weight was highly significant and fairly high. The clean fleece weight in relation to staple length showed a high cor- , lation at each of the respective ages. The shrinkages of fleece in relation V, staple length showed a uniform but negative correlation for each of p, e respective ages which indicates that as the staple length increases I ere is a general tendency for the shrinkage of the fleece to decrease. so in a comparison of staple length in its relation to diameter of fiber '_ e correlation was small and negative but highly significant. DISCUSSION lMerinos and Rambouillets have been laredominant on the sheep ranges I Texas because of their adaptability to the conditions. At the inception the sheep industry in Texas, range breeders were engaged in sheep ising primarily for the production of wool. However, during the past years the range sheep industry has been converted generally to a wool d mutton basis. ~. Under the original program with wool production as the main incentive, eders generally tolerated and in many instances were partial to sheep pssessing a medium to heavy development of skin folds. Their contention s that the increased skin area of the folded or wrinkled Merino or :mbouillet sheep resulted in the production of an increased poundage JThe degree of relationship between two variables increases as correlation coeflicient ap- L ches unity, either 1.00 or — 1.00. No association is indicated by a coefficient of 0.00. The significance or lack of significance depends on both the size of the correlation co- ient and the number of observations on which it is based. 26 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATIQN of wool per‘ animal. The production of wool by relatively smooth-bodied f; Merino and Rambouillet sheep as ‘compared with those which carry ai number of well developed skin folds or wrinkles has long been a subject“ of controversy among sheep breeders both in this country and abroad. They agree in principle, however, that skin folds from a utilitarian stand-i’ point are in many respects undesirable. As a result of the increased demand for lamb and‘ mutton during more recent years, Texas sheep breeders have become partial to the smooth- l" bodied type in the Rambouillet and Merino since lambs or muttons carry- 1 ing avmedium to heavy skin fold development have been severely dis- i criminated against by purchasers of feeders. Furthermore, the skins from»; wrinkly sheep are less valuable than those from smooth-bodied sheepi as discussed by Arnold (1) in 1925. Another important reason why Rani- bouillet and Merino sheep showing heavy skin fold development have, in' the Texas area, met with increasing disfavor among breeders is that they 5 are believed to be more susceptible to strike by blow flies, progenitors of? both the wool worm and the screw worm maggot, than a1'e sheep devoid- of skin folds or wrinkles. Mackerras (18), in 1936, in Australia reported l breech strikes on plain, medium and very wrinkly breeches of Merino ewes overa three-year period. In his study the average percentage of. strikes (blows) per annum on the plain type was 35, on the medium 126, T and on the very wrinkly type 233. A large number of individual fleeces (2640) produced by registered Rambouillet ewes were scoured during the course of this study and a wide range of variation in the weights of scoured fleeces between the respective age groups was shown. Scoured fleeces, 12 months growth, produced bygfl ewes developed and handled under representative range conditions in south- western Texas averaged 3.6 pounds for ages 1 to 11 years with a range L in variability from approximately 2 to 6.3 pounds. Obviously then, with clean 12 months fine wool at a valuation of $1.00 per pound there was a * difference between the lightest and heaviest shearing ewes of $4.30 in. favor of the heavy shearing ewe. It is realized that a goal of 6 pounds clean wool for all Rambouillet ewes grazed under range conditions can“ probably never be attained. It does however serve to emphasize the im-z‘ portance of clean fleece weight in its relationship to increased efliciencyl in range sheep production. As has been stated, B type ewes produced fleeces which on an unscoured basis averaged one pound heavier at 12 ‘ months growth than those produced by C‘ type or smooth-bodied ewes,’ On a scoured basis this difference disappeared. The fleeces produced by; the B type ewes which carried considerable skin fold development showed an average shrinkage of 62.93 per cent as compared with 59.41 for those produced by the C type or smooth-bodied ewes, or a difference of 3.52? points. Texas wool growers quite generally evaluate their annual wo0l~ clip on the basis of unscoured fleece weights. Hence as a result of this practice sufficient emphasis has not been given to clean weights of fleecesr However, until the economics of wool marketing in Texas have been de-‘ veloped to the point where the individual producer is paid directly on the g ax-n INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 27 basis of clean wool, considerable attention should be continued to be given , by the producer to unscoured fieece weights even though it may be neces- " sary to tolerate some skin folds to maintain unscoured fleece weight. Density of wool fibers per unit area of skin surface, although recognized ' as an important factor in relation to fleece weight in fine wool sheep, was not measured in our experiment. It is generally recognized that fine wool fleeces of average or better length showing compactness or density not i to’ be more desirable from the manufacturers standpoint. Studies relating to density of wool fibers on fine wool sheep have been ’ reported by a number of workers. Hultz and Paschal (13) in 1930 reported a study ‘with a low of 14,332 and a high of 54,600 fibers per square inch e cn the shoulder area of Rambouillets that had been exhibited at the Inter- g national Livestock Exposition" in Chicago. Bell and Associates (2) in 1936 reported an average density per square inch of skin surface on ten Amer- l ican Merino ewes and one ram as being 23,985 as compared with an average . of 40,156 on ten Tasmanian Merino ewes and one ram. Bosman (4) in ~ 1941 in South Africa reported that 50 well-bred Merino ewes devoid of skin folds showed a low of 30,200 to a high of 71,600 wool fibers per 5 square inch. Bosman also reported that Merino stud flocks in South Africa may be expected to produce between 30,000 and 60,000 wool fibers per A square inch in contrast to an expectation of 15,000 to‘ 25,000 for grade fine wool flocks. This is in close agreement with Carter (7 ) in Australia, it who in 1942 reported that fiber density among mature Australian Merinos varies from as low as 15,000 to as high as 80,000" per square inch of skin 1 area. He estimated that the best Australian studs averaged better than 50,000 fibers per square inch. Carter (8) in 1943 also directed attention to follicle types and skin fold patterns in the Australian Merino sheep. i’ A determination of the number of wool fibers per unit area on the lunshorn sheep is somewhat technical and involved. It is therefore believed ,e.eby workers in the field at the Texas Station that individual scoured fleece 5vreights will provide adequate information to stud breeders‘ desirous of it further improving fleece weight. Obviously scoured fleeces weighing 5 pounds or more for 12 months’ {production by Rambouillet ewes may be expected to show considerable ;-,density and good length of staple. The average unscoured weight of Texas fleeces in 1942 according to the National Association of Wool Manu- facturers (21) was 7.2 pounds. Based on a shrinkage of 61 per cent, “estimated by that authority, the average scoured fieece weight for Texas wool in 1942 was only 2.8 pounds, a figure which no doubt could be in- ‘creased as a result of systematic culling. grange flocks by a “touch” system in which much emphasis was placed on idensity and length of staple. In 1921 he also reported (10) a sufficiently V ‘Breeders who may be interested in gaining additional information relating to clean ‘lzfleece weights should communicate with the Agricultural Experiment Station Wool Scouring ‘Laboratory at College Station, Texas, for detailed information with reference to methods selecting and packing fleeces, also scouring cost. only yield more wool than open fleeces but the dense fleeces are likely. Hill (9) in 1921 described a method of culling light shearing sheep from» 28 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION high correlation between a fleece produced after maturity and the weight of subsequent fleeces produced by the same sheep to make culling effective. ' Light shearing ewes could be culled from Texas range flocks based on‘ such a method, as pointed out by Lush and Jones (17) in 1923. McMahon_ (19) in New Zealand in 1940 suggested that under a wisely directed pro- l gram of progeny testing and culling, unscoured fleece weights cculd be increased by one pound in a single generation. This study of the influence of age, type, and fertility on Rambouillet . ewes on fineness of fiber, fleece weight, length of staple and body weight . has made available to breeders of Rambouillet and Merino sheep con- siderable information that should prove helpful. ACKNOWLEDGMENTS The authors make grateful acknowledgment of the contributions and ! services of E. M. Peters, formerly Superintendent of the Ranch Experiment ; Station, and to O. L. Carpenter, Livestock Overseer, whose daily care ’ of the sheep and careful attention to the routine records of the breeding flock has contributed greatly to the value of the results reported in this g bulletin. Acknowledgment is also made to the painstaking work in the wool laboratory by Mrs. Emmett Smith for the faithful and painstaking work in obtaining diameter of fiber measurements, and finally to Professor . C. B. Godbey, of the Department of Genetics, A. & M. College of Texas, a for helpful suggestions relating to the arrangement and presentation of if; the data. A SUMMARY AND CONCLUSIONS 1. ‘In this study, extending over 18 years, the influence of age, body type and fertility in Rambouillet ewes on (a) fleece weight and shrinkage, -, (b) staple length, (c) fineness of fiber, and (d) body Weight after the l spring shearing has been reported. 2. Maximum production of unscoured wool basis 12 months growth i. was returned by both the B and C type ewes during the fourth age year. i The differences however in unscoured fleece weights during the third and r fourth years were not significant. 3. Three hundred sixty-six unscoured fleeces from B type Rambouillet i. ewes averaged 9.93 pounds as compared with an average of 8.91 pounds for 2296 fleeces from C type ewes, or 1.02 pounds heavier for the B type a GWQS. 4. All differences in fleece weight practically disappeared in scouring, J and on a clean basis the average fleece weight produced by the C type ' Rambouillet ewes was 3.60 pounds as compared with 3.66 pounds for the B type ewes, or a difference of 0.06 pound which was not significant. 5. Three hundred sixty-six fleeces from B type ewes showed an average shrinkage of 62.93 per cent in scouring as compared with 59.41 per cent . for 2274 fleeces produced by C type ewes. The shrinkage of 460 fleeces produced by C type Rambouillet rams averaged 62.8 per cent in scouring INFLUENCE OF AGE, TYPE AND FERTILITY IN RAMBOUILLET EWES 29 g as compared with 64.6 per cent for 130 fleeces produced by B type rams. iDiiferences in unscoured fleece weights as produced by the C and B types jpractically disappeared in scouring. a ~ 6. Twenty-two hundred seventy-four fleeces produced by C type Ram- iuibouillet ewes showed an average staple length of 2.28 inches as compared Qwith 2.05 inches for 365 fleeces produced by B type Rambouillet ewes. This is a difference of 0.23 inch, an amount which in many instances was suffi- gcient to place C type fleeces in the strictly combing class. _ 7. Staple length after adjustment to 12 months growth, produced by }ewes sheared at one year of age averaged 2.49 inches, or a significantly greater length than staple produced at any of the succeeding ages. A psignificant positive correlation was found between staple length and un- scoured fleece weight, and also between staple length and clean fleece ffweight. 8. Between the ages of 1 and 6 years the staple length had decreased £50.31 inch or about 12 per cent. Between the ages of 1 and 8 years staple length had decreased 0.44 inch or about 18 per cent. i“ 9. After the fourth year there was a slight but consistent decline in fleece weight both on an unscoured and scoured basis at each subsequent age year. The decline in unscoured fleece weight between the ages of 4 and 8 years averaged 1.18 pounds and on a scoured basis 0.53 pound. This Qrepresents an average annual decline of approximately 0.3 pound unscoured land 0.13 pound clean wool. V 10. The fiber diameter of wool produced by Rambouillet ewes during Qithe first age year averaged slightly but significantly finer than at any fiof the subsequent ages. Diameter of wool fiber, however, remained rela- gtively constant after the first year. 11. The wool produced by the C type or smooth-bodied ewes was more i1uniform in diameter or fineness than that produced by B type ewes and éaveraged 0.23 inch longer. 12. Rambouillet ewes used in this study continued to increase in body “Qweight through the fifth year of age. The average weight at that age fjlfOl‘ the sheared ewes was 114 pounds. After the sixth year there was a fismall but gradual decline in body weight. 13. The unscoured fleeces of the Rambouillet ewes that dropped lambs Zduring a given year produced fleeces that averaged 0.57 pound per head iless than fleeces produced by ewes that did not lamb during the year. The fscoured fleeces. produced by the fertile ewes averaged 0.27 pound per gfleece below the production of the Rambouillet ewes that failed to lamb. 14. The shrinkage of 1944 fleeces produced by fertile ewes showed an fiitaverage shrinkage of 60.03 per cent as compared with 59.52 per cent for Zfleeces produced by non-lambing ewes. _; 15. The length of staple produced by ewes that lambed during a given ear averaged 0.08 inch less than that of the non-lambing ewes. 16. Diameter of fiber produced by the fertile ewes averaged slightly l’ rser than was produced by ewes that did not lamb during a given year. 30 BULLETIN NO. 657, TEXAS AGRICULTURAL EXPERIMENT STATION 17. Body weight differences between B and C type ewes of all ages was not significant. 18. Ewes that droptped lambs during any given year averaged 7.6 pounds less in body Weight at shearing time than those that did not lamb. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. REFERENCES Arnold, John R., 1925. Hides and Skins, pp. 365-366, A. W. Shaw Company, Chicago. Bell, D. S., Spencer, D. A., and Hardy, J. I., 1936. The Influence of Various Factors Upon the Growth and Quality of Fine Wool as Obtained from Merino Sheep, Ohio Agr. Expt. Sta. Bul. 571. Bosman, V., 1935. The Influence of Pregnancy and Lactation on Merino Wool Produc- tion. Onderstepoort Jour. Vet. Sci. and An. Ind., 4 (2): 551-556. Bosman, V., 1941. Studies on Merino Wool Production, I and II, Onderstepoort Jour. Vet. Sci. and An. Ind., 17 (1 & 2): 319-344 and 345-350. Burns, Robt. H., and Koehler, W. B., 1925. The Micrometer Caliper as an Instrument for Measuring the Diameter of Wool Fibers, Wyo. Agr. Expt. Sta. Bul. 141. Burns, Robt. H., 1935. The Micrometer Caliper for Measuring the Thickness of Wool Fibers, Wyo. Agr. Expt. Sta. Bul. 204. Carter, H. B., 1942. Density and Some Related Characters of the Fleece of the Aus- tralian Merino, Jour. Council Sci. & Ind. Res., 15 (3): 217-220. Carter, H. B., 1943. Studies in the Biology of the Skin and Fleece of Sheep, Council for Sci. & Ind. Res., Commonwealth of Australia. Bul. 164. Hill, J. A., 1921. Judging Range Sheep for Wool, Wyo. Farm Bul., 10 (3): 10-22. Hill, J. A., 1921. Studies in the Variation and Correlation of Fleeces from Range Sheep, Wyo. Agr. Expt. Sta. Bul. 127. Hill, J. A., 1922. Micrometer Calipers for Teaching the Discrimination of ‘the Fineness of Wool, Proceedings of the American Society of Animal Production, 1921 meeting. Pub. 1922, DD. 8-11. Hultz, Fred S., 1927. Wool Studies with Rambouillet Sheep, Wyo. Agr. Expt. Sta. Bul. 154. Hultz, Fred S., and Paschal, Leo J., Agr. Expt. Sta. Bul. 174. Jones, J. M., Warwick, B. L., and Davis, S. P., 1932. A Preliminary Comparison of Fleeces from B and C type Rambouillets, Proceedings of the 24th Annual Meeting of American Society of Animal Production, pp. 242-243. Jones, J. M., Warwick, B. L., Dameron, W. H., and Davis, S. P., 1935. Eifect of Age, Sex and Fertility of Angora Goats on the Quality and Quantity of Mohair, Tex. Agr. Expt. Sta. Bul. 516. Jones, J. M., Homeyer, Paul, Davis, S. P., Dameron, W. H., Warwick, B. L., 1936. A Comparison of Fleeces from B and C Type Rambouillet Ewes, Proceedings of the 29th Annual Meeting of the American Society of Animal Production, pp. 155-158. Lush, J. L., and Jones, J. M., 1923. The Influence of Individuality, Age and Season Upon the Weights of Fleeces Produced by Range Sheep, Tex. Agr. Expt. Sta. Bul. 311. Mackerras, I. M., 1936. The Sheep Blow Fly Problem in Australia, Council for Sci. & Ind. Res., Commonwealth of Australia, Pamphlet No. 66, Melbourne, Australia. McMahon, P. R., 1940. Increased Profits from Sheep Through Progeny Testing and Culling for Production, Proceedings of the 9th Annual Meeting of Sheep Farmers, Massey Agricultural College, Palmerston North, New Zealand, pp. 37-51. Maré, G. S., and Bosman, V., 1934. The Influence of Feed on the Merino Sheep, Onder- stepoort Jour. of Vet. Sci. and Ani. Ind., 3 (1): 199-210. National Association of Wool Manufacturers, 1942 Bulletin, 72: 118. Nordby, Julius E., 1943. Improving Rambouillet Sheep for Western Ranges, National Wool Grower, 33 (3): 12-17. Pohle, E. M., and Keller, H. R., 1943. Jour. of Ani. Sci., 2 (1): 33-41. Snedecor, G. W., and Cox, G. M., 1935. Disproportionate Subclass Numbers in Tables of Multiple Classification, Iowa Agr. Expt. Sta. Res. Bul. 180. Spencer, D. A., Hardy, J. I., and Brandon, Mary J., 1928. Factors that Influence Wool Production with Range Rambouillet Sheep, U. S. Dept. Agr. Tech. Bul..85. Wilson, J. F., 1931, The Influence of the Plane of Nutrition Upon Various Factors Re- lated to Wool Production, National Wool Grower, 21 (12): 23-28. 1930. Wool Studies with Rambouillet Sheep, Wyo. Staple Length in Relation to Wool Production,