Genetic trends in the expected progeny difference of the asymptotic weight of Nelore females
Genet. mol. biol
;
29(4): 648-652, 2006. graf, tab
Artículo
en Inglés
| LILACS
| ID: lil-450486
ABSTRACT
There are few studies on weight covering the full life cycle of Zebu cattle, and there is no entire growth description or mean growth pattern for animals belonging to this breed. In order to provide such data, 1,158 Nelore females born between 1985 and 1995 were weighed 14,563 times from birth to full growth maturity, in ten herds spread over seven Brazilian states. The Von Bertalanffy, Brody, logistic and Gompertz non-linear models were used to obtain the asymptotic weights (A) and the maturation rates (K). The (co)variance and breeding value components for A and K were obtained by using the multiple trait derivative free restricted maximum likelihood method under the animal model. Genetic trends were calculated in function of the mean expected progeny differences (EPD) for the trait (A or K) divided by the number of animals according to their year of birth. The genetic trends of the expected progeny difference with reference to the date of birth of the cows were, on average, -6.5g y-1 for A and 2.0g y-1 for K, close to zero as confirmed by the low (0.0023 to 0.003) coefficient of regression values. The curve parameters are recommended as a selection criterion to reach precocity and avoid adult weight increase in the female herd.
Texto completo:
Disponible
Índice:
LILACS (Américas)
Asunto principal:
Selección Genética
/
Bovinos
/
Aumento de Peso
Tipo de estudio:
Estudio pronóstico
Límite:
Animales
País/Región como asunto:
America del Sur
/
Brasil
Idioma:
Inglés
Revista:
Genet. mol. biol
Asunto de la revista:
Genética
Año:
2006
Tipo del documento:
Artículo
País de afiliación:
Brasil
Institución/País de afiliación:
Universidade Estadual Paulista/BR
/
Universidade Federal de Tocantins/BR
/
Universidade de São Paulo/BR
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