Genetic variation and covariation in beef cow and bull fertility.

Mackinnon, M. J.; Taylor, Joseph J.; Hetzel, D. J. S.

doi:10.2527/1990.6851208x

Cited by 31 publications

(17 citation statements)

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“…Paralelamente, o perímetro escrotal tem sido preconizado como característica indicadora da puberdade em machos e nas fêmeas que apresentam algum parentesco com eles. Existe suporte na literatura para se concluir que os fatores hormonais que promovem o desenvolvimento testicular inicial nos machos são os mesmos que promovem o desenvolvimento ovariano inicial nas fêmeas, e a seleção para a puberdade precoce em um sexo resultará em associada redução da idade a puberdade do outro sexo (MACKINNON et al, 1990).…”

Section: Análises Envolvendo Mais De Uma Variávelunclassified

Estudo das associações genéticas entre perímetro escrotal e características reprodutivas de fêmeas Nelore

Gressler¹,

Bergmann²,

Pereira³

et al. 2000

R. Bras. Zootec.

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RESUMO -Os objetivos deste trabalho foram estimar parâmetros genéticos para as características perímetro escrotal (PE), medido aos 12 (PE12, n = 652) e 18 (PE18, n = 607) meses de idade, idade ao primeiro parto (IPP, n = 1582), datas do primeiro (DPP, n = 1582) e segundo partos (DSP, n = 644) e primeiro intervalo de partos (PIP, n = 644) de animais da raça Nelore. Os parâmetros foram estimados pelo método da máxima verossimilhança restrita, usando-se um modelo animal e incorporando 15.648 informações de pedigree. As estimativas de herdabilidade das análises incluindo somente uma variável foram 0,24±0,10; 0,31±0,10; 0,01±0,03; 0,11±0,05; 0,07±0,08; e 0,10±0,10, respectivamente, para PE12, PE18, IPP, DPP, DSP e PIP. Estas estimativas foram semelhantes às obtidas nas análises em que foram incluídas duas variáveis, com exceção da análise incluindo os dois PE (0,68 e 0,61 para PE12 e PE18, respectivamente). As estimativas de correlações genéticas entre PE12 e IPP, DPP, DSP e PIP foram, respectivamente, -1,00; -0,08; -0,71; e -0,37. Por outro lado, as correlações genéticas entre PE18 e as características observadas nas fêmeas foram, na mesma ordem, -1,00; 0,21; -0,35; e -0,44. A seleção para o PE12 seria mais efetiva que a seleção para o PE18, quando se deseja obter melhorias relacionadas às características reprodutivas das fêmeas. Palavras-chave: correlação genética, reprodução Genetic Association among Scrotal Circumference and Female ReproductiveTraits in Nellore ABSTRACT -The objectives of this work were to estimate of genetic parameters for scrotal circumference (SC) at 12 (SC12, n = 652) and 18 (SC18, n = 607) months of age, age at first calving (AFC, n = 1,582), first (FCD, n = 1,582) and second (SCD, n = 644) calving dates and first calving interval (FCI, n = 644) in Nellore cattle. Parameters were estimated using REML methodology, with animal models and considering the relations among 15,648 animals. Heritability estimates from univariate analyses were .24±.10, .31±.10, .01±.03, .11±.05, .07±.08 and .10±.10, respectively, for SC12, SC18, AFC, FCD, SCD and FCI. These values were close to the estimates from bivariate analyses, except for the analysis including both SC (heritability estimates of .61 and .68, respectively, for SC12 and SC18). Genetic correlation estimates between SC12 and, respectively, AFC, FCD, SCD and FCI were -1.00, -.08, -.71, and -.37. In the same order, genetic correlation between SC18 and female reproductive traits were -1.00, .21, -.35 and -.44. The selection for SC12 would be more effective than selection for SC18 when trying to improve the reproductive traits of the females. IntroduçãoOs trabalhos disponíveis na literatura brasileira relativos à avaliação da eficiência reprodutiva da fêmea zebu têm enfatizado quase exclusivamente a idade à primeira cria e o intervalo de partos (ANDRADE,1991). Embora possam ser utilizadas para expressar a qualidade reprodutiva dos rebanhos, essas duas características podem não ser as mais adequadas para a seleção e o descarte das fêmeas bovinas de cort...

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Section: Análises Envolvendo Mais De Uma Variávelunclassified

Estudo das associações genéticas entre perímetro escrotal e características reprodutivas de fêmeas Nelore

Gressler¹,

Bergmann²,

Pereira³

et al. 2000

R. Bras. Zootec.

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“…Meyer et al (1990) obtained heritabilities of 0.08, 0.02 and 0.08 for calving success in Herefords, Angus and Zebu crosses respectively, while Mackinnon et al (1990) reported an average heritability estimate for cow fertility of 0.11. The heritability of 0.08 for longevity was also low and corresponds with other estimates (Parker et al, 1959;Miller et al 1967;Hudson & Van Vleck, 1981).…”

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

confidence: 99%

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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“…However, there is significant genetic variation between cows in the interval from calving to first breeding, which is positively correlated with number of services per conception (NSC) (Milagres et al. 1979; Mackinnon et al. 1989; Meyer et al.…”

Section: Introductionmentioning

confidence: 99%

Modelling number of services per conception of Japanese Black cattle by random regression

Nishida

Aziz

Nishida

et al. 2006

J Animal Breeding Genetics

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Repeated records of number of services per conception (NSC) were collected on 607 Japanese Black cows. Data were analysed by random regression (RRM) and multiple trait (MTM) models, considering NSC in each parity as a separate trait. The chosen RRM included additive genetic and permanent environmental effects fitted with a third-order Legendre polynomials of parity. Heritabilities (h2) estimated by RRM decreased along the NSC trajectory from 0.15 in the first parity to 0.04 in the sixth parity and then increased up to 0.22 in the 10th parity. The corresponding estimates obtained by MTM ranged between 0.04 in parity 9 and 0.13 in parity 1. Permanent environmental proportions (p2) of the total phenotypic variance estimated by RRM showed similar pattern and magnitude to those of h2 estimated by the same method. On the contrary, the p2 estimated by MTM ranged between 0.04 in the first parity and 0.11 in the 10th parity. Additive genetic (r(G)), permanent environmental (r(P)) and phenotypic (r(PH)) correlations were also estimated. The values estimated by RRM between adjacent parities were higher than those of parities far apart. The corresponding values estimated by MTM were lower than those estimated by RRM with no certain trend. The results indicated that NSC in heifers is more heritable than NSC in cows with different parities. Reproductive traits are economically important traits and hence, they should be considered in breeding goals.

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Genetic variation and covariation in beef cow and bull fertility.

Cited by 31 publications

References 0 publications

Estudo das associações genéticas entre perímetro escrotal e características reprodutivas de fêmeas Nelore

Estudo das associações genéticas entre perímetro escrotal e características reprodutivas de fêmeas Nelore

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

Modelling number of services per conception of Japanese Black cattle by random regression

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