Grease Fleece Weight Research Articles

Effect of Crossing Merino with Barki sheep on Some Wool Characteristics: II.- Grease Fleece Weight, Fiber Diameter Crimps, Density and Fiber Type Ratio

Effect of Crossing Merino with Barki sheep on Some Wool Characteristics: II.- Grease Fleece Weight, Fiber Diameter Crimps, Density and Fiber Type Ratio

Estrus in range lambs and its relationship to life-time reproductive performance.

The occurrence of estrus in lambs the first winter as related to subsequent lamb production was studied in 2,364 Rambouillet, 1,956 Targhee and 1,350 Columbia ewes. These ewes made one to five lambing records. Twelve percent of the lambs exhibited heat their first winter. The differences among years within breeds were highly significant for each breed. However, the years having a high or low incidence of estrus do not correspond for the three breeds indicating a year-breed interaction. About 60% had one heat period, 25% two heat periods and only 2% had as many as five heat periods. The lambs which came into heat had lower inbreeding coefficients, less face covering, better condition scores, heavier weaning weights, were slightly older and had heavier yearling fall bodyweights than lambs that did not come into heat. The cumulative lamb production was without exception greater for ewes which showed estrus as lambs than for those which did not. The effect was greatest in the Rambouillet breed, being significant for all cumulative lamb production traits but one. Targhee ewes showed an important and significant positive association of estrus and production for the first 3 yr. of production but little association thereafter. The Columbias showed an apparent effect in favor of ewes showing estrus as lambs. However, this was significant only for the lifetime kilograms of lamb weaned per ewe for ewes completing five production records. Rambouillet, Targhee and Columbia ewes showing estrus as lambs accumulated an average of 20.4, 10.9 and 19.1 kg. of lamb more per ewe, respectively, over five production years than those which did not come into heat. There was no significant association of early estrus and lifetime wool production, although in two of the three breeds lifetime grease fleece weights were slightly lower for the groups showing estrus their first winter.

Wool characteristics of Iraqi Awassi sheep

The physical wool characteristics of 268 Iraqi Awassi ewes were studied in 1963, as well as the relationship between some of these traits. The overall average grease fleece weight, clean wool percentage, staple length, fibre length, fibre diameter and degree of crimp were 3·77 lb., 84·85%, 16·47 cm., 17·37 cm., 33·32/t and 4·18 crimps per 2 cm. respectively. These attributes class the Awassi wool as a carpet wool.Age proved to have no significant effect on any ofthe traits examined. Significant positive correlations were found between grease fleece weight and fibre length and between number of crimps and fibre diameter, while a significant negative correlation was found between clean wool percentage and fibre length.

Effects of Pregnancy, Parturition, and Lactation Upon Wool Production of Range Ewes

The effects of breeding group, age of ewe, year, weight of ewe, staple length, type of parturition, lactation, and subsequent pregnancy on grease and clean wool production were studied on 2424 records of grease and 1451 clean fleece weights. The ewes were classified according to the type of parturition, lactation and subsequent pregnancy. The grease and clean fleece weights used in this study were taken just prior to lambing. This allowed most of the effects due to the three factors under study to be reflected in the wool yield. The average grease fleece weight was 7.07 lb., and the average clean fleece weight was 3.60 lb. Partial regressions of clean fleece weight on staple length, body weight of ewe, and grease fleece were 0.09 lb., 0.02 lb., and 0.32 lb., respectively. The regressions of grease fleece weight on staple length and body weight of ewe were 0.20 lb. and 0.04 lb., respectively. The effects of parturition and lactation on wool production were very pronounced, with ewes giving birth and nursing twin or single lambs producing significantly less clean and grease wool than ewes producing no lambs. The effects of pregnancy were less pronounced than those of parturition and lactation. Ewes pregnant with a single lamb did not produce significantly less grease wool than ewes which failed to lamb; however, the difference in clean wool yield was significant. These results indicate that wool records should be adjusted for the effects of lactation and pregnancy before the records are used in a selection program.

Relative Accuracies of Several Methods of Estimating Clean Fleece Weight

Relative accuracies of several methods of estimating clean fleece weight were tested on whole, clean fleece data from 418 Rambouillet, Targhee and Columbia sheep at the U. S. Sheep Experiment Station, Dubois, Idaho. In most instances the correlations between regression equation estimates of clean fleece weight and actual whole, clean fleece weight were higher than correlations between estimates obtained by any other method and whole, clean fleece weight. The most accurate regression equation in this study reduced the standard error of estimate by an average (over all grades) of 2.4% under that obtained using the side sample estimate, 13.3% under grease fleece weight, and 20.1% for machine reading. The regression equations presented were derived from data which were entirely independent of the data on which they were evaluated and included information on six fleece and body traits. The side sample method was generally superior in accuracy of estimating clean fleece when compared to methods based on single trait observations (grease weight, machine reading, staple length, body weight, number of crimps per inch or visual fleece grade in spinning counts). Although the side sample was superior in a few instances to regression equation methods, its modest superiority appears not to justify the greater time, special equipment and high costs associated with its use. The machine reading was more accurate than grease weight for estimating clean fleece weight in the fine wool grade, while grease weight was superior in estimating clean weight in the remaining blood grades of wool. Other methods were invariably less accurate than those mentioned above for estimating clean fleece weight.

Effect of Management Systems on the Growth of Lambs and Development of Internal Parasitism. I. Dry Lot vs. Two Pasture Rotation Systems

Effects of three management systems, including medication, on the development of internal parasitism in lambs and on their growth were studied. The systems included dry lot confinement (Band 1), transfer of animals to a clean pasture at biweekly intervals (Band 2), and grazing of animals on contaminated pastures (Band 3). Average levels of parasitism acquired by the lambs in Bands 1, 2, and 3 were insignificant, moderate, and high, respectively. Lambs from Band 3 acquired significant infections of Haemonchus contortus by June, which continued to rise until midsummer, and heavy infections of Strongyloides papillosus in August and September. Lambs from Band 2 acquired peak moderate infections of H. contortus by midsummer and moderate to heavy infections of S. papillosus in August and September. Clinical haemonchosis in Bands 2 and 3 was not satisfactorily controlled by supplementary therapeutic dosing with N.F. grade phenothiazine. Limited evidence suggested that this may have been due, in part, to a tolerance for the drug. Circumstances did not permit a fair evaluation of copper sulfate drenches in this regard. Average daily gains of lambs in Band 1, until weaning, were significantly greater than those of lambs in Bands 2 and 3. Effect of management and parasitism on weight gains of the lambs became more pronounced in the three Bands after weaning and reached a maximum in early August. Band 3 lost weight on the average during this period. Significant differences in grease fleece weights of the exeperimental animals also were obtained when they were yearlings; the average fleece weights of these three bands were inversely proportional to the degree of parasitism observed during the previous grazing season. Internal parasitism is the most serious problem of the sheep industry in humid areas of the United States. Losses amount to several million dollars annually and deter expansion of the sheep industry in the farm states. Much of the research concerning management practices versus parasitism has been done abroad, particularly in the British Isles and Australia. A series of reports by Spedding (1954, 1955, 1956) from England indicates that proper management exclusive of anthelmintics can greatly reduce the worm burden of sheep, resulting in greater weight gains and an increase in wool production. Gibson (1956), another English worker, concluded from a 3year experiment that the following factors favored n increase in parasitism: returning the sheep to previously grazed pastures too soon, inadequate use of anthelmintics, and weather conditions favorable to larval survival. Gordon and Turner (1946) also demonstrated that rotational grazing retarded the acquisitio of parasites by sheep under Australian conditions. Since climatic conditions have a pronounced effect on the transmission of internal parasites, management research needs to be conducted in various areas on a long-term basis. Research reported in this paper constitutes 1st-year results of a long-term project at Beltsville, Maryland, involving detailed studies on the effects of various management systems, including medication, on the development of internal parasitism in lambs. Preliminary reports of this work have been given by Kates et al. (1960), Turner et al. (1960), Enzie et al. (1960), and Lindahl et al. (1961). Received for publication 6 November 1962. * Animal Husbandry Research Division, ARS, Beltsville, Maryland. t Present address: Food and Drug Administration, Beltsville, Maryland. $ Animal Disease and Parasite Research Division, ARS, Beltsville, Maryland.

Repeatability of Grease fleece weight, Staple length and Body weight before shearing in Corriedale sheep

[in Japanese]

A Comparison of Five Methods of Estimating Clean Fleece Weight

Clean fleece weight obtained by scouring the whole fleece from a total of 139 yearling ewes and 61 yearling rams was compared to (1) the results obtained from scouring small side samples, (2) multiple regression equations predicting clean fleece weight from wool density, body weight, staple length and grease fleece weight, (3) a method described by Neale and McFadden (1954) and (4) the results obtained from a new machine designed by P. E. Neale for estimating clean fleece weight. All methods of estimation appear to be reasonably accurate as shown by the correlation coefficients between whole fleece scouring and each of the four methods described above. These correlations were 0.92., 0.95, 0.87, and 0.87, respectively. It was shown by the multiple correlation coefficients that very little information concerning clean fleece weight is lost in predicting clean fleece weight by the multiple regression method if wool density and body weight were omitted from these equations. The small increase in accuracy of the small sample and multiple regression methods over the machine method does not compensate for the saving of time and expense involved as the machine method requires less than 2 min. per fleece for the estimate. The machine requires no technical skill or knowledge for its operation and is applicable to all flocks. Also, the clean fleece weight estimate derived from the machine is independent of all other traits.

Effects of age on grease fleece weight staple length and body weight of corriedale ewes with regard to the relationshlp among three characters

Effects of age on grease fleece weight staple length and body weight of corriedale ewes with regard to the relationshlp among three characters

Estimation of Clean Fleece Weight from Small Side Samples and from Wool Density, Body Weight, Staple Length and Grease Fleece Weight

Estimation of Clean Fleece Weight from Small Side Samples and from Wool Density, Body Weight, Staple Length and Grease Fleece Weight

A Rapid Method for the Estimation of Clean Fleece Weight with the Aid of a New Wool Density Device

A new device for the measurement of the relative density called the Neale Density Meter was described. Regression equations were constructed for the prediction of the clean fleece weight (CFW) of range yearling and mature fine wool Rambouillet rams. Body weight (BW), staple length (SL) and density (D) were used in the prediction equations. There were available 110 yearling and 57 mature rams for this analysis. The prediction method was designed to be rapid so that selection on the basis of CFW may be made directly in the field. Grease fleece weight (GFW) also entered the analysis to investigate its relationships to the other variables and to be used in the prediction whenever it was available. The following highly significant correlations between CFW and the other variables were obtained (within age groups): BW=.4O, SL=.41, D=.32, and GFW=.63. The correlation of GFW with each of the other variables was smaller in each case than the correlation of that variable with CFW. There was no significant correlation between any two of the three variables: BW, SL and D. The multiple correlation coefficient (R) of CFW with BW, SL, D and GFW was .81 for the yearlings and .75 for the matures. When GFW was eliminated the corresponding R's were .70 and .71, respectively. Measured in terms of the net variation in CFW associated with each of the other variables, their order of importance in prediction is:yearling—1st SL, 2nd GFW, 3rd BW, 4th D; mature 1st SL, 2nd D, 3rd BW and 4th GFW. In the case of yearlings the standard deviation of CFW was .57 pounds. When BW alone was used in prediction the S.E. of estimate became .52, when SL was added it became .43, and when D was added it became .41, and when GFW was added it became .34 pounds. The corresponding figures for the mature group are: .82, .76, .67, .59 and .56. It was concluded that the method of prediction should prove useful in selecting breeding animals. Certain suggestions thought to further increase the accuracy of prediction, without interfering with the practicability of the method, were made.

The Relation of Face Covering to Lamb and Wool Production in Range Rambouillet Ewes

The lifetime lamb production of 798 Rambouillet ewes born during the years of 1938 through 1940 at the Western Sheep Breeding Laboratory, Dubois, Idaho, was studied in relation to face covering. Ewes with open faces produced 11.3 percent more lambs and 11.1 more pounds of lamb per ewe bred than those with covered faces. Ewes with partially covered faces weaned 8.6 percent more lambs and 7.7 more pounds of lamb per ewe bred than those with covered faces. Differences in face covering within these groups were associated with corresponding differences in lamb production. These advantages for ewes with open faces occurred in spite of three periodic clippings around the eyes of all ewes subject to wool blindness. About 46 percent of the advantage of open-faced ewes was due to a greater number of lambs born per ewe lambing; 26 percent was due to higher weaning weights; 19 percent was attributed to a higher proportion of the ewes becoming pregnant; and 9 percent was due to greater viability to weaning of offspring. Open-faced ewes excelled covered-faced ewes in lamb production at each year of age. The greatest advantage for open-faced ewes in pounds of lamb per ewe bred was found at 3 years of age followed in order by 2, 4, 6, and 5 years. The yearling grease and clean fleece weights and staple lengths of 2499 Rambouillet ewes and the lifetime grease fleece weights of 798 Rambouillet ewes were slightly greater for covered-faced ewes than for those with open faces. The differences were not significant except for staple length and were not large enough to be economically important. The great economic importance and high heritability of face covering indicate that it should receive as much or more attention in selection than any other trait in sheep if wool blindness is a problem.

Effects of Some Environmental Factors on Yearling Traits of Columbia and Targhee Rams

The effects of age of dam, type of birth, year of birth, age at shearing and percent inbreeding on grease fleece weight, clean fleece weight, staple length, body weight, type, condition, face covering and neck folds were studied on 359 Columbia and 213 Targhee yearling rams. These rams were born during the years 1941 through 1945. The effect of environmental factors was greatest on grease fleece weight, body weight and clean fleece weight and least on face covering and staple length. Year of birth was the most important environmental source of variation and age of dam was least important. Age of dam was more important in Columbias while age at shearing was more important in Targhees. Single rams had heavier bodies and fleeces than twins. Fleece and body weights, staple length, type and condition improved with increasing age at shearing and became poorer with inbreeding. Inbreeding had a greater detrimental effect on body weight, type and condition than on other traits. Inbreeding had a noticeably greater effect on Targhees than on Columbias. Greater effectiveness of selection is the practical result of adjusting for environmental effects. Accuracy of selection of Columbia and Targhee rams may be increased by adjusting grease fleece weights, clean fleece weights body weight, type and condition for differences between years; grease fleece weight, clean fleece weight and body weight for age at shearing; body weight for type of birth; grease fleece weight and body weight for age of dam in Columbias; and body weight, type and condition for inbreeding in Targhees.

Effects of Some Environmental Factors on Yearling Traits of Columbia and Targhee Ewes

The effects of age of dam, type of birth, year of birth, age at shearing and percent inbreeding on staple length, grease fleece weight, body weight, type, condition, face covering and neck folds were studied on 406 Columbia and 290 Targhee yearling ewes at the U. S. Sheep Experiment Station, Dubois, Idaho. The ewes were born during the years 1941 to 1944. The effect of the environmental factors was greatest on fleece weight and body weight and least on face covering and neck folds. Year of birth was the most important environmental source of variation followed by type of birth, age at shearing, and percent inbreeding. Age of dam was the least important source of variation of Columbia and Targhee yearling traits. Single ewes had heavier bodies and fleeces, longer staple and better type and condition than twins. Daughters of mature dams had heavier fleeces and bodies than those of 2-year-old dams. Fleece and body weights, staple length, type and condition improved with age at shearing and became poorer with inbreeding.

Breed Crosses used in the Development of Targhee Sheep

Data on weaning weight, staple length, type, condition, face covering and neck folds were studied on 599 Targhee lambs and 415 breed-cross lambs at the U. S. Sheep Experiment Station, Dubois, Idaho. Also data on yearling grease fleece weight, staple length, body weight, type, condition, face covering and neck folds were studied on 439 Targhee ewes and 262 breed-cross ewes. In addition, available data from some of these ewes on clean yield, clean fleece weight and commercial grade of fleece were examined. Breed crosses were compared with Targhees to determine their suitability for foundation Targhee breeding. Columbia×Rambouillet ewes excelled in body weight, type, condition, fleece weight, and open face but were deficient in staple length and freedom from neck folds. Rambouillet×Corriedale ewes excelled in staple length, yearling weight, fleece weight, and freedom from folds, but were deficient in type, condition and face covering. Both of these crosses produced grades of fleeces which were fairly typical of Targhees. These crosses complement each other in that one is strong in the traits in which the other is weak. Crosses of Targhee rams on Corriedale and Lincoln-Rambouillet ewes produced ewes which were equal to or better than Targhees in most traits. These crosses produced exceptional length of staple but more of their fleeces were classified in coarser grades than were fleeces of Targhees. The cross of Targhee rams on Rambouillet ewes was least satisfactory for production of Targhees. This cross was inferior to Targhees in every trait at weaning. Yearling body weight, type and condition were better than Targhees, although the shorter staple, more covered faces, and greater degree of neck folds persisted. The yearling fleeces graded definitely finer than Targhees.