Within-herd genetic analyses of stayability of beef females

Snelling, W. M.; Golden, Bruce L.; Bourdon, R. M.

doi:10.2527/1995.734993x

Cited by 76 publications

(89 citation statements)

References 10 publications

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“…The heritabilities for the different stayability levels are in close agreement for both models, therefore, only results from model one are discussed. Heritability estimates for stayability were low, and in agreement with Parker et al (1959), Miller et al (1967, Schaeffer (1975), Van Doormaal et al (1986) and Snelling et al (1995). Hudson & Van Vleck (1981) obtained estimates of 0.02, 0.04, 0.05, 0,05 and 0.05 at 36, 48, 60, 72 and 84 months, respectively in a Holstein herd.…”

Section: Figure 2 Calving Percentage Of Dams Of Different Dam-birth Amentioning

confidence: 64%

Heritability estimates derived from threshold analyses for reproduction and stayability traits in a beef cattle herd

Westhuizen¹,

Schoeman

Jordaan³

et al. 2001

SA J. An. Sci.

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The object of this study was to estimate heritabilities and sire breeding values for stayability and reproductive traits in a composite multibreed beef cattle herd using a threshold model. A GFCAT set of programmes was used to analyse reproductive data. Heritabilities and product-moment correlations between predicted breeding values for stayability at 36, 48, 60, 72 and 84 months of age, calving success and longevity were estimated. The estimated heritabilities on the underlying scale for these traits were 0.06, 0.10, 0.06, 0.03, 0.11, 0.03 and 0.08 respectively. Product-moment correlations between breeding values for stayability traits were low. The highest correlation of 0.22 was obtained between the ages of 36 and 48 months. Heritability estimates and correlations between traits appear to be of such a low magnitude that selection for these characteristics would result in limited genetic improvement, and also indicate that sires had little influence on the stayability, longevity or calving success of their daughters.

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Section: Figure 2 Calving Percentage Of Dams Of Different Dam-birth Amentioning

confidence: 64%

Heritability estimates derived from threshold analyses for reproduction and stayability traits in a beef cattle herd

Westhuizen¹,

Schoeman

Jordaan³

et al. 2001

SA J. An. Sci.

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“…A Method 91 procedure was used in the context of maximum a posteriori (MAP) procedures appropriate to threshold models (Gianola & Foulley 1983). The MAP-Method 91 approach provided estimates of direct, maternal, and permanent environmental components of lamb survivability (Reverter et al 1994;Snelling et al 1995;Evans 1996;Kaiser 1996).…”

Section: Discussionmentioning

confidence: 99%

Threshold model analysis of lamb survivability in Romney sheep

Welsh

Garrick

Enns

et al. 2006

New Zealand Journal of Agricultural Research

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of 80.8%. Lambs were born between 1997 and2000. Fixed effects fitted in the model included sex and contemporary group, defined as the interaction of age of dam, flock, and birth date class. Median heritabilities were 0.106 ± 0.010 for direct, 0.082 ± 0.005 for maternal, and a median proportion of phenotypic variation 0.098 ± 0.003 for permanent environmental effects. The direct-maternal correlation was -0.75 ± 0.03. Estimated breeding values on the underlying scale were back-transformed to the phenotypic probability scale. For direct lamb survivability, the highest performing sire's lambs had a 14.8% greater chance of survival than the lowest performing sire's lambs for flocks with an average lamb survivability of 80%. Although heritabilities for both components of lamb survivability are low, selection for this trait can be accomplished and is of economic importance for the sheep breeder.Keywords lamb survival; sheep; estimated breeding values; heritability; threshold model Abstract Lamb survivability is a major determinant of the reproductive efficiency of the flock. The objective of this study was to estimate variance components for direct, maternal, and permanent environmental components of lamb survivability. Threshold model procedures were used to estimate variance components from 25 362 lamb survival observations representing 136 sires from two Romney flocks in New Zealand with an average lamb survival A06028;

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“…A baixa herdabilidade de DPP, associada à baixa correlação genética entre PE e DPP, sugere a necessidade do estudo de outras características que possam avaliar diretamente a fertilidade da fêmea e que tenham maior herdabilidade. Uma destas características é a habilidade de permanência das vacas no rebanho ou stayability (Snelling et al, 1995). Estes autores encontraram valores de herdabilidade para a habilidade de permanência variando de 0,11 a 0,14.…”

Section: Característicaunclassified

Análise genética de características reprodutivas na raça Nelore

Pereira

Eler

Ferraz

2002

Pesq. agropec. bras.

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Resumo O objetivo deste trabalho foi estimar os coeficientes de herdabilidade da idade ao primeiro parto, dias para o parto (DPP), duração da gestação (DG) e perímetro escrotal (PE) bem como a correlação genética entre perímetro escrotal e estas características reprodutivas medidas nas fêmeas, na raça Nelore. A idade ao primeiro parto foi avaliada em fêmeas expostas pela primeira vez ao touro em torno de 14 meses de idade (IPP14), e em fêmeas expostas ao touro em torno de 26 meses (IPP26). Foram analisados conjuntos de dados que variaram de 6.030 a 94.637 observações. As análises foram processadas utilizando-se modelos animais bi-característica. Os coeficientes de herdabilidade obtidos em relação às características reprodutivas foram: 0,19 (IPP14), 0,02 (IPP26), 0,07 (DPP), 0,26 (DG), e 0,47 (PE). As correlações genéticas obtidas foram: -0,39 (PE e IPP14), -0,19 (PE e IPP26), 0,02 (PE e DPP) e 0,02 (PE e DG). Concluiu-se que a idade ao primeiro parto pode ser utilizada como critério de seleção para precocidade sexual, e que a seleção de touros com base no mérito genético para PE pode resultar na diminuição da idade ao primeiro parto de suas filhas. A baixa herdabilidade obtida quanto aos DPP, associada com a sua baixa correlação com PE, sugerem a necessidade do estudo de outras características que possam avaliar diretamente a fertilidade da fêmea.Termos para indexação: bovinos, correlação genética, parâmetros genéticos, herdabilidade. Genetic analysis of reproductive traits in Nelore cattleAbstract The objective of this paper was to estimate heritability coefficients for age at first calving, days to calving (DC), gestation length (GL) and scrotal circumference (SC) as well as genetic correlations between scrotal circumference and these reproductive traits measured in the females, in Nelore cattle. The age at first calving was evaluated in females mated for the first time around 14 months of age (AFC14) and in females mated for the first time around 26 months of age (AFC26). Datasets varying from 6,030 to 94,637 observations were analyzed. Analyses were processed using two-trait animal models. Heritability coefficients obtained for reproductive traits were: 0.19 (AFC14), 0.02 (AFC26), 0.07 (DC), 0.26 (GL), and 0.47 (SC). The genetic correlations were: -0.39 (SC and AFC14), -0.19 (SC and AFC26), 0.02 (SC and DC); and 0.02 (SC and GL). It was concluded that age at first calving may be used as a selection criterion for sexual precocity and that the selection of bulls for SC can result in daughters with decreased age at first calving. The low heritability obtained for DC, associated to its low genetic correlation with SC, suggest the need of studies on other traits to evaluate female fertility.Index terms: bovines, genetic correlation, genetic parameters, heritability.(1) Aceito para publicação em 7 de agosto de 2001. IntroduçãoO perímetro escrotal está associado à qualidade do sêmen e à libido em touros jovens (até a idade de um ano para Bos taurus e dois anos para Bos indicus) e tem sido uma característica import...

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Within-herd genetic analyses of stayability of beef females

Cited by 76 publications

References 10 publications

Heritability estimates derived from threshold analyses for reproduction and stayability traits in a beef cattle herd

Heritability estimates derived from threshold analyses for reproduction and stayability traits in a beef cattle herd

Threshold model analysis of lamb survivability in Romney sheep

Análise genética de características reprodutivas na raça Nelore

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