Genetic parameters for milk production traits and breeding goals for Gir dairy cattle in Brazil

Abstract Text: Genetic and phenotypic parameters were estimated based on 22,468 lactations records of Gir cows. Statistical analyses were carried out by an animal model, in multitrait analyses using the REML method. A bioeconomic model was developed to calculate economic values. Expected economic responses to selection were compared for two breeding goals: 1) only milk yield (HGL1); 2) milk yield plus fat and protein yields (HGL2). Heritability estimates for milk, protein and fat yields were 0.33 ± 0.02, 0.26 ± 0.02 and 0.24 ± 0.02, respectively. All phenotypic and genetic correlations were high and positive. Economic values for milk, fat and protein were US$0.18, US$0.27 and US$7.04, respectively. The expected responses for HGL1 and HGL2 were US$79.82, and US$127.37, respectively. These results indicated that milk components traits should be included in breeding goals for the Dairy Gir Breeding Program in Brazil.

Keywords:

Gir dairy cattle

economic selection index

economic value