Genetic trends in the expected progeny difference of the asymptotic weight of Nelore females

Genetics and Molecular Biology

Analía Del Valle Garnero¹  Cintia Righetti Marcondes¹  Ricardo José Gunski¹  Henrique Nunes De Oliveira²  Raysildo Barbosa Lôbo² 

[1] ,Universidade Federal de Tocantins Laboratório de Genética, Ciências Biológicas Porto Nacional Tocantins ,Brazil

关键词: adult weight;    bovine(s);    genetic trends;    maturation rate;    simulation with growth curves;   

DOI  :  10.1590/S1415-47572006000400012

来源: SciELO

【 摘 要 】

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.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License