Data/hora: 02/06/2024 06:54:17

Biblioteca(s): | Embrapa Pecuária Sudeste.
Data corrente: | 06/12/2011
Data da última atualização: | 13/10/2015
Autoria: | PANETTO, J. C. do C.; VAL, J. C.; MARCONDES, C. R.; PEIXOTO, M. G. C. D.; VERNEQUE, R. da S.; FERRAZ, B. S.; GOLDEN, B. L.
Afiliação: | JOAO CLAUDIO DO CARMO PANETTO, CNPGL; FACULDADE DE MEDICINA DE RIBEIRÃO PRETO/RIBEIRÃO PRETO; CINTIA RIGHETTI MARCONDES, CPPSE; MARIA GABRIELA CAMPOLINA D PEIXOTO, CNPGL; RUI DA SILVA VERNEQUE, CNPGL; FACULDADE DE ZOOTECNIA E ENGENHARIA DE ALIMENTOS-USP/PIRASSUNUNGA; POLYTECHNIC STATE UNIVERSITY/SAN LUIS OBISPO.
Título: | Female fertility in a Guzerat dairy herd: Heterogeneity of variance components for calving intervals.
Ano de publicação: | 2011
Fonte/Imprenta: | Journal Animal Science, v. 89, (E-Suppl. 1); Journal of Dairy Science, v. 94, (E-Suppl. 1), p.25, 2011
Idioma: | Português
Conteúdo: | Our objectives were to determine if variance components of calving intervals varied with age and if considering calving intervals as a longitudinal trait would be a superior approach for fertility analysis of zebu dairy herds. Calving records from females born from 1940 to 2006 in a Guzerat dairy subpopulation in Brazil were analyzed in the present study. Contemporary groups, formed by year and farm at birth or at calving, ages at calving, equivalent inbreeding coefficients and day of the year were included as fixed effects in the models. Calving interval (CI) was first analyzed by fitting a random regression model with Legendre polynomials of order 3 for the fixed effect of age at calving, and random effects of animal and permanent environment. In a second approach, a multivariate analysis was conducted, includingage at first calving (AFC), first calving interval (CI1), calving interval for young females (CIY) and calving interval for mature females (CIM). Finally, a bivariate analysis was performed for AFC and CIwhere calving intervals were considered as a single trait in a repeatability model. Additionally, ranking of sires were compared among approaches. Calving intervals decreased with age until females were about 80 mo old, remaining nearly constant after that age. A quasilinear increase of 11.5 d on the calving intervals was observed for each 10% increase in the female?s equivalent inbreeding coefficient. Heritability of AFC was 0.37 from both analyses. In the case of CI,the genetic variance ratios ranged from 0.064 to 0.141, depending onthe approach and on the ages at calving. Differences among genetic variance components for calving intervals observed along the animal&#8242;slifetime confirmed the longitudinal aspect of this trait, indicating the importance of such consideration when accessing fertility of zebu dairy females in situations where the available information relies ontheir calving intervals. Changes observed in the ranking of sires suggested that the genetic progress of the population can be affected bythe approach chosen for the analysis of calving intervals
Palavras-Chave: | Guzerat; Varianace components.
Thesaurus Nal: | dairy cattle; female fertility.
Categoria do assunto: | G Melhoramento Genético
Registro original: | Embrapa Pecuária Sudeste (CPPSE)
Exemplares: | CPPSE - (20753-1) - UPC - RA - PP - PROCI-2011.00189 - PAN - 2011.0189 - DIS