How much is a genetically superior ram worth?

1994 ◽  
Vol 45 (2) ◽  
pp. 403
Author(s):  
C Wade ◽  
M Goddard
Keyword(s):  
Discount Rate ◽  
Level Scheme ◽  
Genetic Difference ◽  
Economic Value ◽  
Fibre Diameter ◽  
Multiple Ovulation ◽  
Industry Practice ◽  
Breeding Schemes ◽  
Fleece Weight ◽  
Australian Merino

The economic value of a genetic difference between rams was estimated for stud and commercial tiers in the Australian Merino industry. Discounted returns were predicted using the method of Hill (1974). Results were generated for breeding schemes considering natural mating (Scheme A), artificial insemination (Scheme B), the use of home-bred sires at daughter stud level (Scheme C) and the use of culled stud ewes in lower tiers (Scheme D). The effects of discount rate and ram flock life were assessed. The value of one extra unit of genetic merit in three traits (Clean Fleece Weight, Fibre Diameter and WOOLPLAN index score) was found for commercial, daughter and parent tiers. One extra kilogram of clean fleece weight (CFW) was worth around $817 for a commercial level ram (all Schemes) and up to $390000 for a parent level ram in Scheme B. The same improvement was worth $4 per semen dose used at commercial level, and up to $3977 at parent stud level (Scheme B). Increasing the discount rate devalued later returns, reducing the number of discounted expressions. Increasing ram flock life increased ram value but reduced semen value. The results are discussed for current industry practice and values obtained previously for commercial rams. The economic value of multiple ovulation and embryo transfer is considered.

Corrigendum - How much is a genetically superior ram worth?

1994 ◽  
Vol 45 (2) ◽  
pp. 403
Author(s):  
C Wade ◽  
M Goddard
Keyword(s):  
Discount Rate ◽  
Level Scheme ◽  
Genetic Difference ◽  
Economic Value ◽  
Fibre Diameter ◽  
Multiple Ovulation ◽  
Industry Practice ◽  
Breeding Schemes ◽  
Fleece Weight ◽  
Australian Merino

The economic value of a genetic difference between rams was estimated for stud and commercial tiers in the Australian Merino industry. Discounted returns were predicted using the method of Hill (1974). Results were generated for breeding schemes considering natural mating (Scheme A), artificial insemination (Scheme B), the use of home-bred sires at daughter stud level (Scheme C) and the use of culled stud ewes in lower tiers (Scheme D). The effects of discount rate and ram flock life were assessed. The value of one extra unit of genetic merit in three traits (Clean Fleece Weight, Fibre Diameter and WOOLPLAN index score) was found for commercial, daughter and parent tiers. One extra kilogram of clean fleece weight (CFW) was worth around $817 for a commercial level ram (all Schemes) and up to $390000 for a parent level ram in Scheme B. The same improvement was worth $4 per semen dose used at commercial level, and up to $3977 at parent stud level (Scheme B). Increasing the discount rate devalued later returns, reducing the number of discounted expressions. Increasing ram flock life increased ram value but reduced semen value. The results are discussed for current industry practice and values obtained previously for commercial rams. The economic value of multiple ovulation and embryo transfer is considered.

Comparison of three Australian Merino strains for wool and body traits. I. Genetic means of studs and strains and their interactions with years and sexes

1970 ◽  
Vol 21 (5) ◽  
pp. 815 ◽  
Author(s):  
N Jackson ◽  
EM Roberts
Keyword(s):  
Large Strain ◽  
Genetic Difference ◽  
Fibre Diameter ◽  
New Classification ◽  
Wool Production ◽  
Weight Yield ◽  
Diameter Fibre ◽  
Fleece Weight ◽  
Australian Merino

Samples of breeding age rams and ewes were taken from seven studs representing three strains of Australian Merino, and run in a single environment at Hay, N.S.W. Measurements taken from the ram and ewe progeny of these sheep, born at Hay in 1964 and 1965, were used for a comparative study of wool and body traits of the seven studs. The traits measured were body weight, face cover, folds, greasy fleece weight, yield, clean fleece weight, quality number, character, handle, colour, staple length, crimp frequency, fibre diameter, fibre density, two estimates of the value of wool production per head, and the value of wool production per pound. Large strain and stud within-strain effects were present for both wool and body traits. Strain x year interactions in wool values were attributed to fluctuations in the wool market. Strain x year interaction in fibre diameter reflected variation between the strains in their response to changes in environment, as did stud within-strain x year interactions in greasy fleece weight, yield. and clean fleece weight. Strain x sex interactions were interpreted in relation to a proposed new classification of interactions. The amount of migration between pairs of studs was not related to the present genetic difference between them, for any trait. Schemes for extending the present study to a large number of studs are discussed. Preliminary results of selection experiments have suggested that strains may vary in their response to equal selection pressures.

Effects of inbreeding on four families of Peppin Merinos

1957 ◽  
Vol 8 (3) ◽  
pp. 299 ◽  
Author(s):  
JM Doney
Keyword(s):  
Fibre Diameter ◽  
Genetic Effect ◽  
Direct Consequence ◽  
Specific Gene ◽  
Single Strain ◽  
Merino Sheep ◽  
Fibre Number ◽  
Per Se ◽  
Fleece Weight ◽  
Australian Merino

The influence of inbreeding on several fleece and body characters in a strain of Australian Merino sheep is reported. The four families from which data were taken were derived from a single strain of Peppin Merinos. Inbreeding without selection has been carried on since the foundation of the families between 1939 and 1944. Inbreeding is responsible for a reduction in body size, fertility, greasy and clean fleece weight, and wrinkle score, but has relatively little influence on the fleece components (yield, staple length, fibre diameter, and density of fibre population). It follows that the reduction in fleece weight is a direct consequence of a decrease in total fibre number. Since the reduction in fibre number is likely to be a correlated effect of low pre-natal and early post-natal growth rates, it is suggested that the inbreeding has had no genetic effect on the several independent systems involved in adult wool production but has affected only those associated with fitness and vigour. The depression due to inbreeding therefore may not be caused by specific gene fixation but by increased homozygosity per se.

Studies on Western Australian Merino sheep. 1. Stud, strain and environmental effects on hogget performance

1992 ◽  
Vol 43 (6) ◽  
pp. 1381 ◽  
Author(s):  
RP Lewer ◽  
RR Woolaston ◽  
RR Howe
Keyword(s):  
Fibre Diameter ◽  
Strain Differences ◽  
Average Fibre Diameter ◽  
Weaning Age ◽  
Average Fibre ◽  
Males And Females ◽  
Wool Yield ◽  
Fleece Weight ◽  
Western Australian ◽  
Australian Merino

A 6 year study is reported of Merino studs and strains (Peppin, Collinsville and Bungaree) in Western Australia. Wool and body traits of males and females were measured, with additional subjective traits assessed on females. The effects of strain, stud (within strain), birth year, dam age, birth rearing rank, weaning age and their interactions were estimated using least squares procedures. When tested against studs, strain differences were significant for fibre diameter (both sexes), clean wool yield and about half of the subjective traits (females) but for none of the liveweights. Stud and year effects were significant for all traits, as was their interaction for most traits. Some studs were more stable between years than others in both clean fleece weight and average fibre diameter. Of the remaining effects, birth rearing rank influenced the greatest number of traits, while dam age only affected yield in ewes and some early liveweights. Peppins produced wool 2.0-2.3 microns finer than Bungarees, but not significantly different from Collinsvilles. Peppins also had the best subjective wool scores, but had the highest wrinkle scores and scored poorly on other subjective body traits. Twin-born hoggets produced 0.05-0.15 kg less clean wool than their single-born contemporaries, and their fleeces were about 0.4 microns coarser with poorer subjective qualities. Twins were also lighter from birth (by 23%) up to 17 months (by 5%) in females. Late-born lambs had higher birth weights, but lower subsequent weights, persisting until 12 months in females.

A note on the effect of the F gene on wool production and live weight of Booroola × South Australian Merino rams

1985 ◽  
Vol 40 (2) ◽  
pp. 367-369 ◽  
Author(s):  
R. W. Ponzoni ◽  
M. R. Fleet ◽  
J. R. W. Walkley ◽  
S. K. Walker
Keyword(s):  
Birth Weight ◽  
Fibre Diameter ◽  
Live Weight ◽  
Pleiotropic Effects ◽  
High Fecundity ◽  
Wool Production ◽  
F Gene ◽  
Fleece Weight ◽  
Australian Merino ◽  
Staple Length

ABSTRACTThe effect of the high fecundity Booroola Merino gene (F) on wool production and live weight of Booroola x South Australian Merino rams classified as being offspring of FF, F+ or ++ Booroola sires was investigated. The characters studied were: greasy fleece weight in lambs, hogget (approx. 15 months old) greasy fleece weight and the associated scouring yield, clean fleece weight, fibre diameter, staple length and wool style; birth weight and live weight gains from birth to weaning in September (3 months of age), from September to the following March, and from March to September. There were no significant differences among sire genotypes in the characters studied. The results suggest that the F gene had no undesirable pleiotropic effects on wool and live-weight traits.

Genetic studies of South Australian Merino sheep. 4. Genetic, phenotypic and environmental correlations between various wool and body traits

1982 ◽  
Vol 33 (2) ◽  
pp. 363 ◽  
Author(s):  
IP Gregory
Keyword(s):  
Great Increase ◽  
Fibre Diameter ◽  
Skin Thickness ◽  
Primary Follicle ◽  
Genetic Studies ◽  
Environmental Correlations ◽  
Merino Sheep ◽  
Selection For ◽  
Fleece Weight ◽  
Australian Merino

Genetic, phenotypic and environmental correlations were estimated between 23 quantitative and qualitative wool and body traits of South Australian Merino sheep. Clean fleece weight was significantly correlated genetically with greasy fleece weight (0.62), yield (0.47), staple length (0.41), crimps per inch (-0.34), secondary/primary follicle ratio (0.37) and skin thickness (0.39). No significant half-sib genetic correlation was found between clean fleece weight and fibre diameter and the dam-offspring correlation was quite low, although significant (0.16, P < 0.05). This indicates that selection for clean fleece weight should not lead to any great increase in fibre diameter. Skin thickness is discussed as a possible early indicator of clean fleece weight.

Predicted responses in Merino sheep from selection combining visually assessed and measured traits

2010 ◽  
Vol 50 (10) ◽  
pp. 976 ◽  
Author(s):  
S. I. Mortimer ◽  
K. D. Atkins ◽  
S. J. Semple ◽  
N. M. Fogarty
Keyword(s):  
Fibre Diameter ◽  
Selection Combining ◽  
Breeding Programs ◽  
Dual Purpose ◽  
Merino Sheep ◽  
Merino Wool ◽  
Wool Quality ◽  
Staple Strength ◽  
Fleece Weight ◽  
Australian Merino

Visually assessed traits for wool quality and ease of management are important to Merino sheep breeders and need to be considered in breeding programs. The present study reports on the predicted correlated responses in visual traits from selection using a range of standard MERINOSELECT™ indices available for use in Australian Merino breeding programs. The effect of including a visual trait in the index is also reported. The visual scored traits were classer grade, wool quality (handle, character and colour), conformation (neck and body wrinkle, front and back leg structure) and fleece rot. The indices covered a range of micron premiums of varying emphasis on increasing fleece weight and reducing fibre diameter. The indices were for Merino wool enterprises (Merino 14%, Merino 7% and Merino 3.5%) and Merino dual purpose wool and meat enterprises (Dual Purpose 7% and Dual Purpose 3.5%). The breeding objectives for the indices included fleece weight, fibre diameter, coefficient of variation of fibre diameter, staple strength, bodyweight and reproduction. Selection over 10 years using the standard MERINOSELECT™ indices is predicted to result in a small correlated improvement in the wool quality traits and classer grade, with a slight deterioration in fleece rot score. The improvement in wool handle, character and colour are greater with those indices that have a greater emphasis on reducing fibre diameter than with those increasing fleece weight. Indices with more emphasis on increased fleece weight than on reduced fibre diameter are predicted to result in small increases in neck and body wrinkle scores and a slight deterioration in wool colour. Inclusion of classer grade, handle, character or colour provided slight extra gains in fleece weight for indices that emphasised reduced fibre diameter through increased accuracy of selection.

Genetic studies of South Australian Merino sheep. 3. Heritabilities of various wool and body traits

1982 ◽  
Vol 33 (2) ◽  
pp. 355 ◽  
Author(s):  
IP Gregory
Keyword(s):  
Body Weight ◽  
Fibre Diameter ◽  
Skin Thickness ◽  
Production Traits ◽  
Primary Follicle ◽  
Merino Sheep ◽  
Main Production ◽  
Fleece Weight ◽  
Australian Merino ◽  
Staple Length

Heritabilities have been estimated for a large number of quantitative and qualitative wool and body traits recorded on two flocks of South Australian Merino sheep over a 12-year period. Data were unadjusted for fixed environmental effects and so the estimates are applicable to the heterogeneous populations found in most practical situations. Dam-offspring heritabilities of quantitative traits ranged from 0.15 for primary follicle number to 0.63 for body weight. Greasy and clean fleece weights, percentage clean yield, staple length, crimps per inch, fibre diameter, secondary and total follicle number, skin thickness, coefficient of variation of fibre diameter and secondary/primary follicle ratio had moderate to high heritabilities. Dam-offspring heritabilities of qualitative traits ranged from 0.12 for weather damage of the fleece to 0.75 for birthcoat. Total folds, face cover and hocks had high heritabilities, and wool character, type of staple formation and wool quality had moderate heritabilities. The main production traits (body weight, greasy fleece weight, yield, clean fleece weight, staple length, fibre diameter and total follicle number) were corrected for variation due to type of birth and age of dam and their heritabilities re-estimated. No change occurred in the half-sib heritabilities; dam-offspring heritabilities increased by an average of 0.05.

Direct and maternal genetic (co)variances for hogget liveweight and fleece traits in Western Australian Merino sheep

2002 ◽  
Vol 53 (3) ◽  
pp. 271 ◽  
Author(s):  
S. W. P. Cloete ◽  
J. C. Greeff ◽  
R. P. Lewer
Keyword(s):  
Genetic Correlation ◽  
Coefficient Of Variation ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Phenotypic Variance ◽  
Selection For ◽  
Fleece Weight ◽  
Variance Estimates ◽  
Western Australian ◽  
Australian Merino

(Co)variance estimates for hogget liveweight, greasy fleece weight, clean fleece weight, clean yield, fibre diameter, and the coefficient of variation of fibre diameter were obtained for a Western Australian Merino resource flock. The flock encompassed 16 medium wool bloodlines and data were available for the period 1982–93. Direct additive genetic variances (h2) — expressed as a ratio of the total phenotypic variance within bloodlines — were estimated at 0.52 for hogget liveweight, 0.44 for greasy fleece weight, 0.42 for clean fleece weight, 0.63 for clean yield, 0.71 for fibre diameter, and 0.62 for coefficient of variation of fibre diameter. Maternal genetic variance estimates were significant (P < 0.05) only in hogget liveweight and fibre diameter, but components within bloodlines were low (0.05 for liveweight and 0.02 for fibre diameter). Direct within-bloodline genetic correlations of hogget liveweight as well as greasy and clean fleece weight with fibre diameter were positive (0.17, 0.31, and 0.31, respectively), suggesting that selection for bigger and heavier cutting sheep would generally lead to a broader fibre diameter. Liveweight was unrelated to clean yield and negatively related to coefficient of variation of fibre diameter (–0.17). Greasy fleece weight was negatively related to clean yield (–0.20). The genetic correlation of clean fleece weight with clean yield was positive (0.37). Wool quantity was, in general, positively related to coefficient of variation of fibre diameter, although the estimated genetic correlations were low (0.12 for greasy fleece weight and 0.07 for clean fleece weight). The genetic correlation between fibre diameter and coefficient of variation of fibre diameter was negative, and fairly low (–0.10). These results are discussed with reference to sheep breeding.

Phenotypic and genetic parameters for lamb and hogget traits in a flock of South Australian Merino sheep

1987 ◽  
Vol 27 (2) ◽  
pp. 205 ◽  
Author(s):  
JRW Walkley ◽  
RW Ponzoni ◽  
CHS Dolling
Keyword(s):  
Genetic Parameters ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Merino Sheep ◽  
National Performance ◽  
Adjustment Factors ◽  
Fleece Weight ◽  
Parameter Values ◽  
Australian Merino ◽  
Birth Type

The heritability of and phenotypic and genetic correlations among weaning weight (WW). greasy fleece weight (GFW), scouring yield (YLD), clean fleece weight (CFW), fibre diameter (FD), crimps per inch (CR) and staple length (SL) were estimated in a flock consisting of a control and 2 selection lines of South Australian Merino sheep. The effects of type of rearing, age of dam and sex were also examined. Estimates were compared with those currently in use in WOOLPLAN (National Performance Recording Scheme for non-pedigreed sheep) and in other studies. In general, agreement between the present study and other estimates was good, but there were some exceptions, namely: (i) standard deviation of GFW and FD; (ii) 'adjustment factors' for day of birth, type of rearing and age of dam for GFW, CFW and liveweight traits; (iii) heritability of YLD; (iv) phenotypic correlations of GFW and CFW with FD, and between YLD and CFW and (v) genetic correlations of WW with GFW, CFW and FD. It is concluded that special attention should be given to these exceptions in order to decide whether alterations to current 'accepted' parameter values are justified.

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