Efficiency of wool production of grazing sheep. 1. Differences between merino sheep selected for high and low fleece weight

1969 ◽  
Vol 9 (38) ◽  
pp. 249 ◽  
Author(s):  
BA Hamilton ◽  
JP Langlands
Keyword(s):  
Nitrogen Content ◽  
Merino Sheep ◽  
Wool Production ◽  
Grazing Sheep ◽  
Fleece Weight

The intake, wool production, and efficiency of wool production (wool production per unit intake) of rams drawn from two flocks selected for 13 years for high (Fleece Plus) and low (Fleece Minus) fleece weights were estimated while the rams grazed three pastures differing in the amount of herbage available. In a second experiment the rams were fistulated at the oesophagus and determinations were made of the digestibility and nitrogen content of the samples collected while the sheep grazed two pastures. The wool production, intake, and efficiency of the Fleece Plus rams were greater than those of the Fleece Minus on all pastures. Variability in wool production was primarily attributable to variability in efficiency. Differences between flocks in wool production and efficiency increased when herbage availability and wool production were high.

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.

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.

Effect of stocking rate on fleece measurements and their relationships in merino sheep

1976 ◽  
Vol 27 (1) ◽  
pp. 163 ◽  
Author(s):  
DH White ◽  
BJ McConchie
Keyword(s):  
Fibre Diameter ◽  
Major Determinant ◽  
Stocking Rate ◽  
Merino Sheep ◽  
Wool Production ◽  
Rate Experiment ◽  
Fleece Weight ◽  
One Year ◽  
Staple Length

The wool characteristics of Merino wethers were measured for 6 years in a stocking rate experiment. The decline in fleece weight due to increasing stocking rate from 4.9 to 12.4 sheep per hectare was usually accompanied by a reduction in fibre diameter and staple length and an increase in staple crimp frequency. The magnitude of these responses differed considerably between years; in one year clean fleece weight was reduced by 50%, with an associated reduction of 5 µm in mean fibre diameter and one of 2 cm in staple length. In four of the six years of the experiment, variation in fibre diameter accounted for at least 50% of the variation in wool production between stocking rate treatments. The relationships between clean fleece weight and fibre diameter were similar between years, mean fibre diameter being reduced by about 1.8 �m for each kilogram reduction in clean fleece weight. Fibre diameter is the major determinant of wool price, and this information should improve the prediction of economic responses to changes in stocking rate.

Production and management considerations of running wethers, hemi-castrates and induced cryptorchids for wool production

1997 ◽  
Vol 37 (3) ◽  
pp. 303 ◽  
Author(s):  
F. M. Foster ◽  
R. B. Jackson ◽  
D. L. Hopkins ◽  
R. Corkrey
Keyword(s):  
Effective Means ◽  
Fibre Diameter ◽  
Carcass Characteristics ◽  
The Other ◽  
Partial Reduction ◽  
Merino Sheep ◽  
Wool Production ◽  
Synthetic Hormones ◽  
Fleece Weight ◽  
Full Reduction

Summary. Male, fine wool Merino sheep which had been subjected to different methods of castration as lambs were assessed from 22 to 46 months of age for their suitability for wool production, their tolerance to posthitis and their carcass characteristics. Hemi-castrates produced significantly (P<0.001) more clean wool than induced cryptorchids of a similar fibre diameter. Induced cryptorchids and hemi-castrates were significantly (P<0.05) heavier than wethers. Partial hemi-castrates and induced cryptorchids had significantly (P<0.001) heavier and leaner carcasses (lower GR measurement) than wethers and testosterone-treated wethers. Induced cryptorchidism and hemi-castration proved to be effective means of reducing the prevalence of posthitis such that as the degree of castration decreased the proportion of animals with higher posthitis scores decreased (P<0.001). Testosterone levels in induced cryptorchids (1.01 ng/mL) and hemi-castrates with partial reduction of the parenchyma (0.83 ng/mL) were similar, whereas hemi-castrates with complete reduction of the parenchyma in the 1 remaining testicle had a significantly (P<0.001) lower level (0.32 ng/mL) and significantly (P<0.001) lighter testes. Development of horns and obvious scrotums by induced cryptorchids and hemi-castrates with partial reduction of the parenchyma in the 1 remaining testicle attracted penalty rates at shearing and slaughter. Some induced cryptorchids and hemi-castrates exhibited masculine behaviour, but they were unlikely to be fertile because although spermatozoa were present they were abnormal and/or non-motile. Hemi-castrates with full reduction of the parenchyma in the 1 remaining testicle offer significant advantages over the other groups for wool production. Severe posthitis was not observed, they were infertile, they did not attract penalty rates for shearing or slaughter and their clean fleece weight, wool quality, carcass weight and grade were comparable with or superior to wethers. To reduce dependence on synthetic hormones to control posthitis, traditional complete castration techniques could be replaced with this type of partial castration in wool-producing flocks.

scholarly journals Metabolism of Cystine by Merino Sheep Genetically Different in Wool Production I. Comparison of the Entry Rates of Cystine in Sheep From Flocks Selectively Bred for High and Low Fleece Weight

1972 ◽  
Vol 25 (6) ◽  
pp. 1259 ◽  
Author(s):  
AJ Williams ◽  
RA Leng ◽  
SK Stephenson
Keyword(s):  
Merino Sheep ◽  
Wool Production ◽  
Extracellular Compartment ◽  
Fleece Weight

The rates of entry of cystine into the extracellular compartment, and the concentrations of cystine in this compartment, were measured during 12-14 hr infusions ofL-[35S]cystine in Peppin Merino ewes_ The ewes were sampled from flocks selectively bred for high or low clean fleece weight per head; and were fed either 500 or 1100 g of chaffed lucerne hay daily during the experiment.

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.

scholarly journals Metabolism of Cystine by Merino Sheep Genetically Different in Wool Production III. the Incorporation of Radioactivity Into Wool Fibres During and After Intravenous Infusions of l-[35S]Cystine and its Relationship to Wool Growth and Efficiency of Conversi

1973 ◽  
Vol 26 (2) ◽  
pp. 465 ◽  
Author(s):  
AJ Williams
Keyword(s):  
Merino Sheep ◽  
Wool Production ◽  
Wool Growth ◽  
Intravenous Infusions ◽  
Fleece Weight ◽  
Dietary Treatments

Twelve mature ewes from a flock selected for high clean fleece weight (Fleece Plus) and twelve from a flock selected for low clean fleece weight (Fleece Minus) were randomly divided between two dietary treatments: 500 or 1100 g per day of chaffed lucerne hay.

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.

Early weaning of grazing sheep. 2. Performance of ewes

1976 ◽  
Vol 16 (79) ◽  
pp. 156 ◽  
Author(s):  
JL Corbett ◽  
EP Furnival
Keyword(s):  
Genotypic Differences ◽  
Early Weaning ◽  
Wool Production ◽  
Wool Growth ◽  
Grazing Sheep ◽  
Fleece Weight

Two similar groups of Corriedale ewes were formed from a flock of 231. These were grazed on separate phalaris (Phalaris tuberosa) pasture at 8.6 or 17.3 ewes ha-1, respectively high and low nutritional planes, from seven weeks before their first lambing in spring 1968 until after their second lambing. Within each group the 1968 lambs were weaned by removal to other pastures at six or 12 weeks of age, or were left unweaned for 21 or 29 weeks in the high and low planes respectively. Birth weights in 1968 did not differ between planes, and for all ewes an increase of 1 kg in lamb birthweight was associated with a reduction in clean wool production during the last seven weeks of pregnancy of 0.22 � 0.11 g d-1. Pregnancy appeared to reduce by about one half the expression of genotypic differences between sheep in wool producing ability, and reduced 12 months clean fleece weight by about 5 per cent. Low plane ewes produced significantly less milk containing less solids. Liveweight gains and rates of wool growth were reduced by lactation and increased after weaning, wool growth the more slowly. Both rates of recovery were less in the low plane where, unlike the high plane, lactation appeared to reduce expression of genotypic differences in wool production. Clean fleece weights were reduced by about 5 and 10 per cent by lactations of respectively six weeks and five months duration. At subsequent joining a smaller proportion of the low compared with high plane ewes was marked by the ram and of these a smaller proportion produced lambs. Within the low plane, the longer the preceding lactation the lower the liveweight at second joining and lambing, and the lower the mating and lambing percentages. The results indicated that when there was a shortage of feed at and after lambing the performance of ewes would be improved by weaning their lambs at about six weeks. Ewe liveweights were consistently greater after six week weaning than after later weaning, a result confirmed in other experiments on weaning within fixed total areas of pasture.

Subclinical selenium insufficiency. 5. Selenium status and the growth and wool production of sheep supplemented with thyroid hormones

1994 ◽  
Vol 34 (1) ◽  
pp. 13 ◽  
Author(s):  
GE Donald ◽  
JP Langlands ◽  
JE Bowles ◽  
AJ Smith
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Subcutaneous Injection ◽  
Significant Interaction ◽  
Fibre Diameter ◽  
Selenium Status ◽  
Merino Sheep ◽  
Wool Production ◽  
Grazed Pastures ◽  
Fleece Weight

Fine wool Merino sheep grazed pastures low in selenium (Se) in 2 experiments, and were supplemented with Se and thyroxine (T4) in experiment 1, and with Se, T4, and tri-iodothyronine (T3) in experiment 2. Both experiments ran for 6 months. In experiment 1, 72 sheep with a mean liveweight of 37 kg were given Se by intraruminal pellet and 6 levels of T4 ranging from 0 to 10 mg sodium L-thyroxine as a subcutaneous injection at 14-day intervals. In experiment 2, 36 sheep with a mean liveweight of 24 kg were given Se by intraruminal pellet, and 3 levels of T4 ranging from 0 to 0.4 mg and 3 levels of T3 ranging from 0 to 0.1 mg by subcutaneous injection at weekly intervals. In both experiments wool production and mean fibre diameter were significantly increased by Se supplementation; the increase in clean fleece production was 7 and 32% in experiments 1 and 2, respectively. In experiment 1, T4 increased greasy fleece weight by up to 8% and reduced yield, mean fibre diameter, and liveweight. In experiment 2, T4 reduced fibre diameter. T3 did not significantly affect wool production, wool characteristics, or liveweight. There was no significant interaction between Se and thyroid hormone supplementation in either experiment. Thyroid hormones were used as effectively for wool production by both Se-deficient and Se-sufficient sheep.

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