Silva Lopes, Jader, Nogara Rorato, Paulo Roberto, Weber, Tomás, Olegário de Araújo, Ronyere, Magda Everling, Dionéia, Bresolin, Tiago, de Almeida Dornelles, Mariana, and Breda, Fernanda Cristina
The objective of this study was to evaluate the genetic divergence among Nellore breed animals raised in 45 farms in the Southern Region of Brazil. The characteristic studied was weaning weight adjusted to 205 days of life (P205), from 10,874 animals sired by 425 bulls and 7,629 cows, collected between 1976 and 2001, and distributed in the states of Rio Grande do Sul (1,499), Santa Catarina (2,332) and Paraná (7,043). The animals were distributed by cluster analysis in eight genetic divergent groups, enabling this technique to be applied to organize the matings in order to obtain heterotic effect. The herd/farm groups were formed through the hierarchical Ward method, using the direct (VGD) and maternal (VGM) breeding values predicted by the REML method. The VGD of the animal accounted for 90% of the differences among herds, and the remaining 10% was attributed to differences in the VGM. On average, the P205for the animals from inter-group mating was 1.4kg higher than those from intragroup mating, representing 2.4% of heterosis. [ABSTRACT FROM AUTHOR]