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Registro Completo |
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Biblioteca(s): |
Embrapa Gado de Leite. |
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Data corrente: |
05/02/2013 |
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Data da última atualização: |
08/02/2024 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
PANETTO, J. C. do C.; VAL, J. E.; MARCONDES, C. R.; PEIXOTO, M. G. C. D.; VERNEQUE, R. da S. |
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Afiliação: |
JOAO CLAUDIO DO CARMO PANETTO, CNPGL; J. E. VAL, USP; C. R. MARCONDES, USP; MARIA GABRIELA CAMPOLINA D PEIXOTO, CNPGL; RUI DA SILVA VERNEQUE, CNPGL. |
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Título: |
Female fertility in a Guzerat dairy subpopulation: Heterogeneity of variance components for calving intervals. |
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Ano de publicação: |
2012 |
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Fonte/Imprenta: |
Livestock Science, v.145, n. 1/3, p. 87-94, 2012. |
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DOI: |
https://doi.org/10.1016/j.livsci.2012.01.002 |
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Idioma: |
Inglês |
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Conteúdo: |
The objectives of the present study were to determine if variance components of calving intervals varied with age at calving and if considering calving intervals as a longitudinal trait would be a useful approach for fertility analysis of Zebu dairy herds. With these purposes, calving records from females born from 1940 to 2006 in a Guzerat dairy subpopulation in Brazil were analyzed. The fixed effects of contemporary groups, formed by year and farm at birth or at calving, and the regressions of age at calving, equivalent inbreeding coefficient and day of the year on the studied traits were considered in the statistical models. In one approach, calving intervals (CI) were analyzed as a single trait, by fitting a statistical model on which both animal and permanent environment effects were adjusted for the effect of age at calving by random regression. In a second approach, a four-trait analysis was conducted, including age at first calving (AFC) and three different female categories for the calving intervals: first calving females; young females (less than 80 months old, but not first calving); or mature females (80 months old or more). Finally, a two-trait analysis was performed, also including AFC and CI, but calving intervals were regarded as a single trait in a repeatability model. Additionally, the ranking of sires was compared among approaches. Calving intervals decreased with age until females were about 80 months old, remaining nearly constant after that age. A quasilinear increase of 11.5 days on the calving intervals was observed for each 10% increase in the female's equivalent inbreeding coefficient. The heritability of AFC was 0.37. For CI, the genetic-phenotypic variance ratios ranged from 0.064 to 0.141, depending on the approach and on ages at calving. Differences among genetic variance components for calving intervals were observed along the animal's lifetime. Those differences confirmed the longitudinal aspect of that trait, indicating the importance of such consideration when accessing fertility of Zebu dairy females, especially in situations where the available information relies on their calving intervals. Spearman rank correlations among approaches ranged from 0.90 to 0.95, and changes observed in the ranking of sires suggested that the genetic progress of the population could be affected by the approach chosen for the analysis of calving intervals. MenosThe objectives of the present study were to determine if variance components of calving intervals varied with age at calving and if considering calving intervals as a longitudinal trait would be a useful approach for fertility analysis of Zebu dairy herds. With these purposes, calving records from females born from 1940 to 2006 in a Guzerat dairy subpopulation in Brazil were analyzed. The fixed effects of contemporary groups, formed by year and farm at birth or at calving, and the regressions of age at calving, equivalent inbreeding coefficient and day of the year on the studied traits were considered in the statistical models. In one approach, calving intervals (CI) were analyzed as a single trait, by fitting a statistical model on which both animal and permanent environment effects were adjusted for the effect of age at calving by random regression. In a second approach, a four-trait analysis was conducted, including age at first calving (AFC) and three different female categories for the calving intervals: first calving females; young females (less than 80 months old, but not first calving); or mature females (80 months old or more). Finally, a two-trait analysis was performed, also including AFC and CI, but calving intervals were regarded as a single trait in a repeatability model. Additionally, the ranking of sires was compared among approaches. Calving intervals decreased with age until females were about 80 months old, remaining nearly constant after that age. A quasi... Mostrar Tudo |
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Palavras-Chave: |
Avaliação genética; Fertilidade da fêmea; Intervalo de partos. |
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Thesagro: |
Variação Genética. |
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Categoria do assunto: |
G Melhoramento Genético |
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Marc: |
LEADER 03172naa a2200229 a 4500
001 1948360
005 2024-02-08
008 2012 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.1016/j.livsci.2012.01.002$2DOI
100 1 $aPANETTO, J. C. do C.
245 $aFemale fertility in a Guzerat dairy subpopulation$bHeterogeneity of variance components for calving intervals.$h[electronic resource]
260 $c2012
520 $aThe objectives of the present study were to determine if variance components of calving intervals varied with age at calving and if considering calving intervals as a longitudinal trait would be a useful approach for fertility analysis of Zebu dairy herds. With these purposes, calving records from females born from 1940 to 2006 in a Guzerat dairy subpopulation in Brazil were analyzed. The fixed effects of contemporary groups, formed by year and farm at birth or at calving, and the regressions of age at calving, equivalent inbreeding coefficient and day of the year on the studied traits were considered in the statistical models. In one approach, calving intervals (CI) were analyzed as a single trait, by fitting a statistical model on which both animal and permanent environment effects were adjusted for the effect of age at calving by random regression. In a second approach, a four-trait analysis was conducted, including age at first calving (AFC) and three different female categories for the calving intervals: first calving females; young females (less than 80 months old, but not first calving); or mature females (80 months old or more). Finally, a two-trait analysis was performed, also including AFC and CI, but calving intervals were regarded as a single trait in a repeatability model. Additionally, the ranking of sires was compared among approaches. Calving intervals decreased with age until females were about 80 months old, remaining nearly constant after that age. A quasilinear increase of 11.5 days on the calving intervals was observed for each 10% increase in the female's equivalent inbreeding coefficient. The heritability of AFC was 0.37. For CI, the genetic-phenotypic variance ratios ranged from 0.064 to 0.141, depending on the approach and on ages at calving. Differences among genetic variance components for calving intervals were observed along the animal's lifetime. Those differences confirmed the longitudinal aspect of that trait, indicating the importance of such consideration when accessing fertility of Zebu dairy females, especially in situations where the available information relies on their calving intervals. Spearman rank correlations among approaches ranged from 0.90 to 0.95, and changes observed in the ranking of sires suggested that the genetic progress of the population could be affected by the approach chosen for the analysis of calving intervals.
650 $aVariação Genética
653 $aAvaliação genética
653 $aFertilidade da fêmea
653 $aIntervalo de partos
700 1 $aVAL, J. E.
700 1 $aMARCONDES, C. R.
700 1 $aPEIXOTO, M. G. C. D.
700 1 $aVERNEQUE, R. da S.
773 $tLivestock Science$gv.145, n. 1/3, p. 87-94, 2012.
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Registro original: |
Embrapa Gado de Leite (CNPGL) |
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