Parameter estimates for number of lambs born at different ages and for 18-month body weight of Rambouillet sheep.

Lee, J W; Waldron, D. F.; Vleck, L.D. Van

doi:10.2527/2000.7882086x

Cited by 14 publications

(11 citation statements)

References 18 publications

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“…Recent REML-estimates for litter size in sheep ranged from 0.05 to 0.26 [4,7,11,14,16,17]. Our REML heritability estimates for LSN are in agreement with these studies.…”

Section: Genetic Parameterssupporting

confidence: 87%

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

2004

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-The litter size in Suffolk and Texel-sheep was analysed using REML and Bayesian methods. Litters born after hormonal induced oestrus and after natural oestrus were treated as different traits in order to estimate the genetic correlation between the traits. Explanatory variables were the age of the ewe at lambing, period of lambing, a year*flock-effect, a permanent environmental effect associated with the ewe, and the additive genetic effect. The heritability estimates for litter size ranged from 0.06 to 0.13 using REML in bi-variate linear models. sheep / litter size / oestrus induction / heritability / genetic correlation

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“…Recent REML-estimates for litter size in sheep ranged from 0.05 to 0.26 [4,7,11,14,16,17]. Our REML heritability estimates for LSN are in agreement with these studies.…”

Section: Genetic Parameterssupporting

confidence: 87%

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

2004

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“…A mean value of 0.07 for h 2 (LSN) in sheep can be computed from REMLestimates published before 1995 [8]. Recent REML-estimates for litter size in sheep ranged from 0.05 to 0.26 [4,7,11,14,16,17]. Our REML heritability estimates for LSN are in agreement with these studies.…”

Section: Genetic Parameterssupporting

confidence: 83%

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

2004

View full text Add to dashboard Cite

The litter size in Suffolk and Texel-sheep was analysed using REML and Bayesian methods. Litters born after hormonal induced oestrus and after natural oestrus were treated as different traits in order to estimate the genetic correlation between the traits. Explanatory variables were the age of the ewe at lambing, period of lambing, a year*flock-effect, a permanent environmental effect associated with the ewe, and the additive genetic effect. The heritability estimates for litter size ranged from 0.06 to 0.13 using REML in bi-variate linear models. Transformation of the estimates to the underlying scale resulted in heritability estimates from 0.12 to 0.17. Posterior means of the heritability of litter size in the Bayesian approach with bivariate threshold models varied from 0.05 to 0.18. REML estimates of the genetic correlations between the two types of litter size ranged from 0.57 to 0.64 in the Suffolk and from 0.75 to 0.81 in the Texel. The posterior means of the genetic correlation (Bayesian analysis) were 0.40 and 0.44 for the Suffolk and 0.56 and 0.75 for the Texel in the sire and animal model respectively. A bivariate threshold model seems appropriate for the genetic evaluation of prolificacy in the breeds concerned. sheep / litter size / oestrus induction / heritability / genetic correlation

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“…Heritability estimates for YWT and 18MW were moderate, at 0.26 and 0.38, respectively, and within the range of estimates reported by Safari et al (2005) for postweaning weights or BW taken after 12 mo of age (0.29) in dual-purpose sheep breeds. Notter and Hough (1997) reported an identical estimate of heritability for YWT in Targhee (0.26) to that reported here, and the heritability estimate for 18MW was similar to the estimate of 0.43 obtained by Lee et al (2000) in Rambouillet sheep.…”

Section: Lamb Traitssupporting

confidence: 82%

Phenotypic and genetic associations between lamb growth traits and adult ewe body weights in western range sheep

Borg

Notter

Kott

2009

Journal of Animal Science

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Data from the Montana State University Targhee flock were used to estimate genetic and environmental relationships between lamb BW and adult ewe BW, condition score, and prolificacy. The flock was managed under commercial western range conditions typical of the area. Data included records from 12,154 lambs born to 2,930 dams and 200 rams between 1960 and 2005. Lamb traits included BW at birth and approximately 45 d, 120 d (weaning), 12 mo, and 18 mo of age and fleece characteristics at 12 mo of age. Adult traits included ewe litter size; BW and BCS at weaning, in late gestation, and in early lactation; and adult fleece measurements. Multiplicative factors were used to adjust (pre)weaning lamb BW for effects of age of dam, type of birth and rearing, and lamb sex and to adjust adult litter sizes for effects of ewe age. An animal model was used to estimate genetic relationships. Models for lamb traits included fixed effects of year of birth and, for postweaning data, lamb sex and random additive genetic effects and, for (pre)weaning BW, additive genetic maternal and permanent environmental maternal effects. Models for adult traits included fixed effects of year of birth, year of record, and, when appropriate, numbers of lambs born or born and reared and random additive genetic and animal permanent environmental effects. Heritability estimates for lamb birth weight, 45-d BW, weaning weight, yearling weight, 18-mo BW, fleece weight, staple length, and spinning count were 0.19, 0.07, 0.12, 0.32, 0.38, 0.32, 0.31, and 0.25, respectively. Maternal heritabilities for lamb birth, 45-d, and weaning weights were 0.15, 0.09, and 0.08, respectively. Heritability estimates for adult traits were 0.12 for litter size, averaged 0.43 for BW and 0.13 for body condition, and were 0.44, 0.37, and 0.25 for adult fleece weight, staple length, and spinning count, respectively. Correlations between genetic effects on adult BW and direct and maternal genetic effects on lamb BW ranged from 0.21 to 0.96 (P < 0.05) and 0.29 to 0.53 (P < 0.05), respectively, with residual correlations ranging from 0.05 to 0.95. Correlations of lamb traits with adult body condition and number of lambs born were generally not different from zero; genetic and residual correlations ranged from -0.52 to 0.69 and -0.39 to 0.31, respectively.

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Parameter estimates for number of lambs born at different ages and for 18-month body weight of Rambouillet sheep.

Cited by 14 publications

References 18 publications

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

Genetic parameters for litter size in sheep: natural versus hormone-induced oestrus

Phenotypic and genetic associations between lamb growth traits and adult ewe body weights in western range sheep

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