Selection for crimp frequency in the wool of Merino sheep. 2. Efficiency of conversion of food to wool

1974 ◽  
Vol 14 (69) ◽  
pp. 441 ◽  
Author(s):  
GE Robards ◽  
AJ Williams ◽  
MHR Hunt
Keyword(s):  
Genetic Correlation ◽  
Merino Sheep ◽  
Wool Production ◽  
Genetic Groups ◽  
Selection For ◽  
Fleece Weight ◽  
Four Levels

Two experiments were conducted in which the efficiency of wool production of Merino sheep selected for increased (Crimps Plus) and decreased (Crimps Minus) crimp frequency, and a randomly selected control flock, was examined under pen feeding conditions. Ewes for the second experiment were chosen from the same genetic flocks as those used in the first experiment, after a further 1.8 generations (six years) of selection. In the first experiment, in which four levels of roughage diet were offered to ewes from each of the genetic groups, Crimps Minus ewes consistently produced more wool and with a greater efficiency than Random ewes, which were superior in these two characters relative to Crimps Plus ewes. Similar results were obtained in the second experiment, in which ewes were fed to maintain liveweight. Wool production and efficiency of Fleece Plus ewes were greater than those of Crimps Minus ewes indicating a higher genetic correlation between efficiency and fleece weight than between efficiency and crimp frequency.

Selection for economic characters in Australian Merino sheep. VI. Inheritance and interrelationships of some subjectively graded characteristics

1955 ◽  
Vol 6 (6) ◽  
pp. 873 ◽  
Author(s):  
FHW Morley
Keyword(s):  
Genetic Correlation ◽  
Reproductive Efficiency ◽  
Agricultural Experiment Station ◽  
Merino Sheep ◽  
Experiment Station ◽  
Agricultural Experiment ◽  
Selection For ◽  
Fleece Weight ◽  
Australian Merino

Genetic and phenotypic relationships among subjectively graded characteristics were examined in a flock of Merino sheep a t Trangie Agricultural Experiment Station. Estimates of heritability were: wool handle, 0.30; wool colour, 0.63; wool character, 0.38; back wool, 0.00; hocks, 0.14; face cover, 0.38. The genetic correlation between face cover and fleece weights suggested that selection for fleece weight would increase "wool-blindness", with possible diminution of reproductive efficiency. Selection for wools of good character (well-defined crimp) would improve softness and would not decrease fleece weight. The conclusion emerging from this and previous studies is that intense selection for high fleece weight will be rewarded by substantial increases, and will be offset only partly by adverse changes in a few of the several characters investigated.

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.

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: WOOL PRODUCTION AND FLEECE CHARACTERISTICS

1987 ◽  
Vol 67 (1) ◽  
pp. 1-11 ◽  
Author(s):  
MOHAMED H. FAHMY
Keyword(s):  
Fiber Length ◽  
Fiber Density ◽  
Wool Production ◽  
Genetic Groups ◽  
Wool Fibers ◽  
Shoulder Region ◽  
Fleece Weight ◽  
Positive Heterosis ◽  
The Relationship ◽  
Fiber Thickness

Wool fibers grown on 2 cm2 of skin were removed from the shoulder region of 273 female yearlings born at La Pocatiere Experimental Farm over a period of 3 yr. The yearlings represented nine genetic groups, Finnsheep, DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. The traits studied were staple length, fiber density, clean wool percentage, fiber length and thickness and their variability. Grease fleece weight (GFW) was recorded at first shearing on the 273 yearlings and on an additional 90 female yearlings. GFW was subsequently recorded at yearly intervals up to the 5th shearing. GFW of Finnsheep (F) was 2.3 kg for yearlings and averaged 2.0 kg for older ewes compared to 2.3 and 2.8 kg for the DLS, respectively. The crosses showed positive deviations from the expected means of their parental breeds, the highest was expressed in the [Formula: see text] and 5/8F crosses, GFW exceeded in many crosses that of the better parental breed. The relationship between GFW and the proportion of Finnsheep in the genetic group was linear in second shearing and curvilinear for later shearings. Significant linear relations were also observed in fiber thickness and variability in both fiber length and fiber thickness, whereas significant curvilinear relations were observed in clean wool percentage and fiber length. Compared to DLS, Finnsheep had a higher fiber density (1950 vs. 1551 cm−2), fibers were longer (19.1 vs. 15.8 cm) more variable in length (SD = 4.66 vs. 2.96 cm), finer (20.5 vs. 25.5 μm, and uniform in fiber thickness (SD = 4.8 vs. 5.9 μm), these differences being statistically significant. Most of the crosses exhibited positive heterosis particularly in clean wool percentage, staple and fiber length. The highest heterosis was often manifested in the [Formula: see text] cross. Key words: Wool production, fleece characteristics, crossbreeding, heterosis, Finnsheep, DLS sheep

Selection for economic characters in Australian Merino sheep. V. Further estimates of phenotypic and genetic parameters.

1955 ◽  
Vol 6 (1) ◽  
pp. 77 ◽  
Author(s):  
FHW Morley
Keyword(s):  
Genetic Correlations ◽  
Minor Importance ◽  
Agricultural Experiment Station ◽  
Genetic Progress ◽  
Sheep Population ◽  
Merino Sheep ◽  
Agricultural Experiment ◽  
Selection For ◽  
Fleece Weight ◽  
Genetic Homeostasis

Estimates of heritability, genetic correlations, phenotypic correlations, and other parameters among eight characteristics were obtained from Merino sheep at Trangie Agricultural Experiment Station. One set of estimates was obtained by parent-offspring regressions from data obtained between 1943 and 1952. Another set was obtained by half-sib analyses from data from sheep with first adult shearings in 1953. Estimates of heritability were: greasy fleece weight, 0.40 ± 0.06; yield (per cent.), 0.39 ± 0.07; clean fleece weight, 0.47 ± 0.07; staple length, 0.56 � 0.07; crimps per inch, 0.47 ± 0.11; folds, 0.50 ± 0.07; body weight, 0.36 ± 0.08; birthcoat, 0.80 ± 0.10. The most important genetic correlation limiting genetic improvement in clean fleece weight is that between this trait and crimps per inch. Because of this the rate of improvement in fleece weight could be reduced by about 30 per cent. whenever crimps per inch is also selected. Other genetic correlations indicate antagonisms between characteristics, but these antagonisms appear to be of minor importance except that between clean fleece weight and crimps per inch. This sheep population does not appear to have reached a state of genetic homeostasis, a t least with respect to the characteristics studied. However, the findings emphasize the necessity for careful evaluation of the economic importance of different traits, and for accurate measurement, if maximum genetic progress is to be achieved.

scholarly journals Genetic parameters for wool traits in Finnsheep lambs

2008 ◽  
Vol 16 (2) ◽  
pp. 124 ◽  
Author(s):  
M-L. PUNTILA ◽  
K. MÄKI ◽  
A. NYLANDER
Keyword(s):  
Genetic Correlation ◽  
Variance Components ◽  
Genetic Parameters ◽  
Fibre Diameter ◽  
Live Weight ◽  
Bivariate Analysis ◽  
Component Estimation ◽  
Selection For ◽  
Fleece Weight ◽  
Staple Length

Genetic parameters were estimated for wool characteristics of white and coloured Finnsheep. The data consisted of 5 309 lambs from ordinary production flocks, the Finnsheep nucleus flock and a breeding flock. The variance component estimation was done applying REML analyses. Wool traits included fleece uniformity, density, staple formation, lustre, crimp frequency, fineness grade and staple length. There was a smaller dataset that contained also lamb live weight, greasy fleece weight and additional fleece characteristics including fibre diameter measured with the OFDA method. The variance components for direct and maternal effects were estimated using bivariate analysis for 42-day, 120-day weight and greasy fleece weight. Heritability for visually assessed wool characteristics varied from 0.23 to 0.43 and for measured traits from 0.45 to 0.62. Staple length had a high negative genetic correlation with crimp frequency and fineness grade. Heritability of greasy fleece weight was high (0.55) and that of fibre diameter 0.62. The genetic correlation between crimp frequency and fibre diameter was negative (- 0.56). The results imply that the assessed traits are useful indicators for fleece quality and those of major importance can be introduced into the breeding programme. The results suggest that there is no antagonism in selection for both growth capacity and wool quantity.;

Corrigendum - Response to partial selection on clean fleece weight in South Australian strong-wool Merino sheep

1969 ◽  
Vol 20 (1) ◽  
pp. 151
Author(s):  
O Mayo ◽  
JC Potter ◽  
RE Brady ◽  
CW Hooper
Keyword(s):  
Fibre Diameter ◽  
Index Method ◽  
Visual Method ◽  
Merino Sheep ◽  
Index Group ◽  
Agricultural College ◽  
Selection For ◽  
The Difference ◽  
Fleece Weight ◽  
Selection Of

This paper reports the results of an experiment carried out at Roseworthy Agricultural College from 1953 to 1966 comparing two bases of selection of rams: (1) visual appraisal (the "visual" method); (2) visual culling of 70% of rams followed by selection of breeding animals from the remaining 30% on the basis of clean fleece weight (the "index" method). No selection for fleece weight was practiced on ewes. Seven rams were used in each of the two flocks, and six of the seven were replaced each year by 16-month-old animals from the succeeding drop, the seventh being a year older. Rams used for breeding in the Index flock were significantly higher in clean fleece weight than those of the Visual flock, and were higher, though not always significantly so, in greasy fleece weight. This led to a divergence between the flocks for clean fleece weight (P < 0.05), with an increase of c. 0.05 lb per year per head for the Index animals over the Visual animals. The Index rams were more wrinkly and lighter, on the whole, than the Visual rams, and the wrinkly effect carried over into their offspring with a slight divergence apparent, the Index animals becoming more wrinkled than the Visual (P < 0.05). In fibre diameter there were no differences between selected animals or between flocks. Visual rams tended to have more crimps per inch in their wool, and this was observed in the flocks also, but the divergence was not significant (P > 0.05). Index rams had longer wool than Visual rams, with the difference generally significant within years, and this tendency carried over in a lesser manner to the flocks. Fleece density was generally greater in the Index group, though not usually significantly so. This experiment did not include a randomly bred control flock, but was rather designed to compare two practical methods of selecting rams. Merits of this scheme are discussed in the light of both groups' failure to show increases in fleece weight over the course of the experiment

A comparative investigation of the volumes of plasma and extracellular fluids and the renal clearances of urea and creatinine in Merino sheep from flocks with different genetic capacities for wool growth

1991 ◽  
Vol 42 (8) ◽  
pp. 1311
Author(s):  
AJ Williams ◽  
KJ Thornberry ◽  
H Nicol
Keyword(s):  
Extracellular Fluid ◽  
Comparative Investigation ◽  
Average Volume ◽  
Castrate Male ◽  
Merino Sheep ◽  
Genetic Groups ◽  
Wool Growth ◽  
Renal Clearances ◽  
Fleece Weight ◽  
Dietary Treatments

Adult castrate male Merino sheep (n = 24; average liveweight 47 kg), from two flocks, differing in their genetic capacity for wool growth as a result of selective breeding for clean fleece weight, consumed one of two diets, differing in both quality (i.e. digestibility and nitrogen content) and quantity, termed L and H. The L (low) and H (high) diets supplied 0.42 and 0.81 kg digestible dry matter day-' and 9.5 and 26.0 g nitrogen day-I respectively. We compared the volumes of plasma and extracellular fluids, as well as the concentration of urea in plasma and the rate of clearance of urea by the kidneys of sheep from these two genetic groups, consuming the different diets. The average plasma volume of these sheep, estimated from the dilution of Evan's Blue in plasma, was 2.24 L (s.e. 0.08). The average volume of extracellular fluid, estimated from the dilution of 35S-sulfate, was 10.3 L (s.e. 0.4). These distributional volumes were similar in sheep from the two genetic groups and were not influenced by the dietary treatments. The sheep consuming the H diet maintained significantly greater concentrations of urea-nitrogen in their plasma (7.2 v. 2.8 mmol L-1: s.e. 0.3) and cleared both urea (37.1 v. 16.1 mL min-I : s.e. 5.3) and creatinine (87 v. 49 mL min-1 : s.e. 11) at significantly greater rates from the plasma. The sheep from the two genetic groups had similar average values for these three traits.

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