Body-weight-fleece-weight relationships in a strain of Merino sheep

1956 ◽  
Vol 7 (1) ◽  
pp. 57 ◽  
Author(s):  
PG Schinckel
Keyword(s):  
Body Weight ◽  
Body Surface ◽  
Unit Area ◽  
Merino Sheep ◽  
Wool Production ◽  
Significant Difference ◽  
The Mean ◽  
Fleece Weight ◽  
Relationship Of ◽  
The Relationship

The relationship of body weight to wool production was examined in a flock of Merino sheep of South Australian strain over a period of 7 years. In only one out of 10 groups examined was there a significant correlation between body weight and the amount of clean wool produced per unit area of midside skin. It is concluded that body weight and wool production per unit area of body surface are independent. In all groups there was a highly significant correlation between clean fleece weight and clean wool per unit area of body surface in the midside region. The regression of log fleece weight on log body weight was determined in 15 groups. In no case was the regression coefficient significantly different from 0.60. As the regression of log surface area on log body weight in sheep is of the order of 0.60, it is concluded that wool production is proportional to fleece-bearing surface. The mean regression coefficients of log fleece weight on log body weight, calculated within sire and year groups, were: rams, 0.52 ± 0.056; ewes, 0.61 ± 0.038; wethers, 0.30 ± 0.068. There were no significant differences between sires in the regression of log fleece weight on log body weight. There were, however, highly significant differences between sire groups in mean log fleece weight, after adjustment for differences in log body weight. Skin areas 3 by 3 cm were tattooed on the left midside of 24 lambs at 1 month of age. The wool produced on these areas, and the areas of the tattoos, were measured at 4-monthly intervals from 4 months of age until 28 months. The amount of wool produced m7as proportional to the area in each of the six periods. There was also a highly significant difference between periods and between sheep in the amount of wool produced after adjustment for differences in tattoo area.

scholarly journals A Relationship Between Sulphur Content of Wool and Wool Production by Merino Sheep

1967 ◽  
Vol 20 (1) ◽  
pp. 153 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks ◽  
OB Williams ◽  
AJ Williams
Keyword(s):  
Body Weight ◽  
Unit Area ◽  
Sulphur Content ◽  
Merino Sheep ◽  
Wool Production ◽  
Weight Index ◽  
Wool Growth ◽  
The Mean ◽  
Fleece Weight ◽  
The Relationship

The sulphur content of wool from 66 Peppin Merino wethers maintained together at pasture was measured in midside staples representing 49 weeks growth. The distribution of sulphur values was normal with a mean of 3�43 % and a range of 3�08-3�92 %. The sulphur content of the wool was inversely related to wool production among these sheep. There were no significant differences in the relationship when wool production was expressed as fleece weight index (F.W.I.), i.e. clean fleece weight/body weight (r = -0�48), as clean fleece weight (r = -0�42), or as wool growth per unit area of skin (r = - 0�37). The mean sulphur content of wool from sheep with the 10 highest values for F.W.I. was 3�27%, compared with a mean of 3 �55% sulphur for wool from sheep with the 10 lowest values for F.W.I.

The value of production from a clipped measured area as an index of fleece weight.

1955 ◽  
Vol 6 (1) ◽  
pp. 91 ◽  
Author(s):  
FHW Morley ◽  
LW Lockart ◽  
EC Davis
Keyword(s):  
Body Weight ◽  
Correlation Coefficient ◽  
Unit Area ◽  
Multiple Correlation Coefficient ◽  
Multiple Correlation ◽  
Merino Sheep ◽  
Wool Production ◽  
Fleece Weight ◽  
Selection Of

The correlation between greasy wool production per unit area, obtained by clipping and measuring an area of about 100 cm² on the midside, and greasy fleece weight at shearing was about 0.58. Wool production from such an area over periods of 7½ or 3½ months was almost as useful as production for 11 months for predicting greasy fleece weight. The multiple correlation coefficient between greasy fleece weight as the dependant variable and production per unit area and 11-months' body weight was 0.79 in 66 rams and 0.71 in 82 ewes. The inclusion of fold score did not improve prediction appreciably. The equation W = P/110 + B1 /12 may be used to predict greasy fleece weight (lb), W, where P is production over 11 months of greasy wool (mg/cm²) and B1 is 11-months' body weight (Ib). A table of this function is included so that values may be read directly. The technique may be a useful aid to selection of Merino sheep if recording of actual fleece weights is difficult or impossible. Nevertheless it should not be regarded as more than a moderately accurate substitute for actual fleece-weighing.

The relationship of lamb birthcoat to adult fleece structure in a strain of Merino sheep

1958 ◽  
Vol 9 (4) ◽  
pp. 567 ◽  
Author(s):  
PG Schinckel
Keyword(s):  
Body Weight ◽  
Fibre Diameter ◽  
Merino Sheep ◽  
Gene System ◽  
Weight Yield ◽  
Fleece Weight ◽  
Relationship Of ◽  
The Relationship ◽  
Staple Length

Variability of the lamb birthcoat has been studied in relation to adult fleece characteristics. Coarse birthcoats were associated with increased variability of fibre diameter and decreased crimp rate. The increased variability of fibre diameter resulted from a significant increase in the diameter of primary fibres and a small, but statistically non-significant, decrease in the diameter of secondary fibres. There was no relation between birthcoat grade and body weight, clean fleece weight, yield, staple length, follicle density, follicle ratio, mean fibre diameter, or skin folds. It is postulated that there is a gene system in the Merino the effect of which is to cause variation in the amount of wool produced by the different follicle types. Increased "dosage" of genes of the system endows primary follicles with increased productivity and secondary follicles with decreased productivity. This is expressed in the form of increased halo-hair abundance in the lamb and increased differences between the diameters of primary and secondary fibres in the adult.

Relationship between follicle number and wool production

1957 ◽  
Vol 8 (5) ◽  
pp. 512 ◽  
Author(s):  
PG Schinckel
Keyword(s):  
Negative Correlation ◽  
Unit Area ◽  
Statistical Significance ◽  
Biological Significance ◽  
Significant Negative Correlation ◽  
Merino Sheep ◽  
Wool Production ◽  
Significant Difference ◽  
Positive Correlations ◽  
The Relationship

The relationship between follicle number per unit area and wool production per unit area was examined in strong-wool (South Australian) and medium-wool (Peppin) Merino sheep. In four groups of strong-wool sheep (varying in number from 103 to 197 sheep) non-significant positive correlations were observed between follicle number per unit area and the amount of clean wool delineated by a 1 in. calliper. In two groups of strong-wool sheep (178 ewes and 169 rams) and one group of medium-wool sheep (184 ewes) the relationship between follicle number and unit area wool production was inferred from the association between number and fibre weight. There was a highly significant negative correlation (r = – 0.45 approx.) between number and fibre weight in each group. Further, a highly significant difference was observed between sire groups in mean fibre weight after adjustment for differences in follicle number. It was concluded that there was a small positive correlation between follicle number and wool production. This association was so small as to be of dubious biological significance. There were strong indications of a negative genetic correlation between follicle number and wool production, although this did not attain statistical significance.

Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weights, body weight and wool quality

1989 ◽  
Vol 40 (2) ◽  
pp. 433 ◽  
Author(s):  
SI Mortimer ◽  
KD Atkins
Keyword(s):  
Body Weight ◽  
Environmental Effects ◽  
Genetic Variance ◽  
Research Centre ◽  
Production Traits ◽  
Merino Sheep ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Fleece Weight

Wool production traits were measured on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits measured were greasy fleece weight (GFW), skirted fleece weight (SKFW), yield (Y), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). These measurements were used to examine genetic differences between and within flocks of Merino sheep, and to estimate heritability of and genetic and phenotypic correlations among these traits. Significant strain, flock within strain and flock effects were present for all traits. Interactions between these effects and year were non-significant. Within-flock genetic variance was always larger than between-flock within strain genetic variance for each trait. The influence of environmental effects on these traits was also examined. The environmental effects of birth-rearing type, age at observation and age of dam together accounted for about 7-10% of the total within-flock variation in fleece weights and body weight.After adjusting for significant environmental effects, paternal half-sib heritability estimates were 0.29 �. 0.06 for GFW, 0.22 � 0.05 for SKFW, 0.35 � 0.05 for Y, 0.30 �0.06 for CFW, 0.48 �0.07 for FD, 0.34 �. 0.06 for BWT and 0.44 �0.07 for SL. Estimates for genetic and phenotypic correlations were in agreement with published estimates except for the genetic correlation between CFW and FD (0.40 �. 0.11), and the genetic correlations involving BWT, which were essentially zero. The implications of the results of this study for the genetic improvement of Merino sheep for wool production are discussed.

Maintenance rations for Merino sheep. IV. The performance of adult Merino ewes fed daily and weekly at three levels of energy intake

1957 ◽  
Vol 8 (1) ◽  
pp. 75 ◽  
Author(s):  
PK Briggs ◽  
MC Franklin ◽  
GL McClymont
Keyword(s):  
Body Weight ◽  
Sodium Chloride ◽  
Energy Intake ◽  
Survival Rates ◽  
Experimental Period ◽  
The Body ◽  
Merino Sheep ◽  
Wool Production ◽  
Body Weights ◽  
The Mean

Dry adult Merino ewes were fed at daily or weekly intervals on oat grain at levels which provided 4.0, 3.0, or 2.0 lb starch equivalent (S.E.) per sheep per week. The experimental periods were 223, 223, and 181 days respectively. Differences between the mean body weights of the ewes a t the three levels of feeding were highly significant (P < 0.001). Body weight varied only slightly and no losses occurred in ewes fed weekly at the rate of 4.0 lb S.E. per head. Ewes fed daily a t this level had a significantly greater mean body weight (P < 0.001) a t the conclusion of the 223-day experimental period. The addition of a sodium chloride supplement did not improve the body weight or wool production of ewes fed weekly a t the level of 4.0 lb S.E. The mean body weight of ewes fed at the levels of 3.0 or 2.0 lb S.E. per head declined over the first 12 and 18 respectively and thereafter remained relatively constant. There were no significant differences at these levels of feeding between groups fed daily and weekly in respect of body weight, wool production, or survival rates. Ewes fed a t the level of 4.0 lb S.E. grew significantly more wool than those given 3.0 lb S.E. (P < 0.001). Losses were negligible in all groups except those fed a t the level of 2.0 lb S.E. In these groups there were few deaths in the first 16 weeks, but in the subsequent 10 weeks losses totalled 17.1 per cent. Ewes fed a t the level of 2.0 lb S.E. consumed their rations at a significantly slower rate (P < 0.01) than did those fed a t the level of 4.0 lb S.E.

Voluntary food intake in relation to body weight among British breeds of cattle

1986 ◽  
Vol 42 (1) ◽  
pp. 11-18 ◽  
Author(s):  
St C. S. Taylor ◽  
A. J. Moore ◽  
R. B. Thiessen
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Linear Regression ◽  
Regression Coefficient ◽  
Natural Logarithm ◽  
The Mean ◽  
Voluntary Intake ◽  
Relationship Of ◽  
The Relationship ◽  
Voluntary Food Intake

ABSTRACTVoluntary food intake and body weight were examined over 4-week intervals between 14 and 70 weeks of age in 306 females from 25 British breeds of cattle. At each age, the relationship of the natural logarithm of voluntary food intake to that of body weight was examined by linear regression both within and between breeds.Of the total variation in voluntary food intake, the proportion accounted for by body weight was extremely high between breeds (phenotypically, 0·80 or more; genetically 0·88 or more, at most ages) but phenotypically low within breeds (0·33 or less). The mean voluntary intake of a breed at any age could be predicted from its mean body weight at the same age with a coefficient of variation (CV) among breeds that declined with age from 0·08 to 0·04. Within breeds, the corresponding CV for individual intake was between 0·12 and 0·15 beyond 9 months of age, and even higher at early ages.Within breeds, the regression coefficient of log intake on log body weight was close to the value of 0·7 at all ages. Between breeds, it was over 0·8 at early ages, declining to about 0·7 beyond 1 year of age. Thus, genetically larger breeds voluntarily consumed relatively more food at early ages compared with later ages. Breed size should therefore be taken into account when recommending food intake requirements. Breed deviations for high and low appetite are discussed.

Study of wool production per unit area of skin in Australian Merino sheep

1957 ◽  
Vol 8 (6) ◽  
pp. 723 ◽  
Author(s):  
RE Chapman ◽  
SSY Young
Keyword(s):  
Unit Area ◽  
The Body ◽  
Marked Variation ◽  
Merino Sheep ◽  
Wool Production ◽  
Body Regions ◽  
The Mean ◽  
Australian Merino

In a study of wool production per unit area of skin of Merino sheep, two strains of ewes, one strain of rams, and five strains of wethers were examined. A marked variation in weight of wool per unit area was found over the body regions of sheep. A distinct dorsoventral gradient, and some anteroposterior gradients were observed. Sampling positions having wool weights per unit area close to the mean over the body were situated on a line from mid-shoulder to mid-thigh positions. This was consistent for all the groups of animals studied. The mean wool production per unit area varied from sheep to sheep and from strain to strain. These differences were large and highly significant irrespective of level of feeding.

The effect of thyroxine on the mean and variance of wool production of Merino sheep on natural pasture

1965 ◽  
Vol 5 (19) ◽  
pp. 376
Author(s):  
CHS Dolling ◽  
LR Piper ◽  
MT Carpenter
Keyword(s):  
Body Weight ◽  
Total Period ◽  
Wool Production ◽  
Dose Rates ◽  
Natural Pasture ◽  
Significant Difference ◽  
Mean And Variance ◽  
The Mean ◽  
Pre Treatment ◽  
Thyroid Secretion

Administration of sodium-1-thyroxine to 14-15 months old medium Peppin Merino wethers resulted in a significant increase in both greasy and clean wool production (P<0.05 in each case) when the wethers were grazing on natural pasture in south-western Queensland. This was demonstrated in an analysis of wool production during a total period of 24 months. Within this period, the wethers treated with thyroxine produced seven per cent more greasy wool per head than did the untreated control sheep (P<0.01) and seven per cent more clean wool (P<0.05) during the 15 weeks following implantation. During the subsequent 17 weeks the treated wethers produced three per cent more greasy wool than the controls (P<0.05), but there was no significant difference in clean wool production. There were no significant differences in either greasy or clean wool production in either of the last two periods of the 24-month experiment. There were no significant differences in wool production among the three groups of wethers whose dose rates at a single implantation were 30 mg, 60 mg, and 90 mg respectively. Administration of thyroxine resulted in a significant increase in the variance of greasy wool production during the 15 weeks following implantation (P<0.05) hut had no effect on the variance of clean wool production. The rate of gain in body weight displayed by all groups that received thyroxine was retarded, but groups had returned to their pre-treatment body weight ranking five months after implantation. Mortality was one per cent per annum among implanted animals over the two years following implantation. It is suggested that the response to thyroxine administered in mid-summer may have resulted partly from making good a seasonal deficiency in thyroid secretion. The tactical use of thyroxine to increase wool production per head in a region of considerable within-year or between-year variation of rainfall characterized by unpredictable flushes of pasture growth is discussed. The limited influence of thyroxine on the variance of wool production does not encourage its use as an aid to selection for clean wool production per head.

SHEARLING AND SECOND-YEAR CLEAN FLEECE WEIGHTS AS AN INDEX OF WOOL PRODUCTION IN THREE BREEDS OF RANGE SHEEP

1958 ◽  
Vol 38 (1) ◽  
pp. 53-60
Author(s):  
S. B. Slen ◽  
E. C. Banky ◽  
H. F. Peters
Keyword(s):  
Regression Coefficients ◽  
Reliable Estimate ◽  
Wool Production ◽  
Breed Differences ◽  
Mature Weight ◽  
Second Year ◽  
Selection For ◽  
Fleece Weight ◽  
Relationship Of ◽  
The Relationship

The relationship of shearling and second-year clean fleece weight to total wool production, i.e., first 5 years of life, was analysed in three breeds of range sheep (Canadian Corriedale, Rambouillet, and Romnelet) to determine its usefulness in selection for increased wool production.A correlation of +.67 (p <.01) between shearling clean fleece weight and the sum of the four mature fleece weights was obtained in the three breeds studied. When the first mature weight (second fleece) was correlated with the total weight of the three subsequent fleeces, the correlation was increased significantly (p <.01). Consequently, the second fleece appeared to be a more reliable estimate of lifetime production than shearling weight. No breed differences in these correlations were found when lifetime production was compared to shearling or to second-year fleece weights. The regression coefficients of lifetime production on shearling fleece weight showed that a shearling ewe which produced 1.0 lb. of clean wool above the average produced approximately 3.0 lb. more than the average during her productive life.Shearling fleece weight was found to represent 83, 77, and 80 per cent of the maximum mature fleece weight in the Canadian Corriedale, Rambouillet, and Romnelet, respectively. No breed differences were observed in this relationship.The repeatability of annual clean fleece weight was found to be.93,.83, and.76 for the Rambouillet, Romnelet, and Canadian Corriedale, respectively.

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