A raça Indubrasil no Nordeste Brasileiro: Melhoramento e estrutura populacional

Abstract

In order to provide knowledge for breeding, conservation programs and expansion policies of the Indubrasil breed from northeastern Brazil, the evolutionary history, estimates of genetic parameters and the populational structure of the breed were studied. Pedigree information was used from animals born from 1964 to 2006 and the adjusted weights at 205, 365 and 550 days of age of bovines born from 1976 onwards. The heritability coefficient estimates were lower than those reported in the literature for the adjusted weights at the three ages (P205: direct 0.11 ± 0,03 and maternal 0.01 ± 0.03; P365: direct 0.16 ± 0.04 and P550: direct 0.15 ± 0.05) and the genetic gains for the evaluated traits decreased in the sampled period (P205: -0.028 kg/year; P365: -0.030 kg/year and P550: -0.025 kg/year). The low genetic variability and the reduced genetic gains were probably due to a reduction in the effective size and increasing inbreeding within the period. Furthermore, the drastic reduction in the number of births per year and the low use of unrelated sires within the herds make the Indubrasil breed a genetic group potentially threatened by extinction, so that conservationist and expansion programmes should be set up. © 2009 Sociedade Brasileira de Zootecnia.