Genetic parameters for economics traits in Saanen and Anglo-nubian goats

Abstract

Heritabilities estimates were calculated for age at first kidding (IPP), kidding interval (IDP), total milk yield (PL) and lactation length (DL) of Saanen and Anglo-nubian goats. Data was collected from 1988 to 2002, at the Dairy Sector of Embrapa Caprinos, Sobral, CE. Heritabilities estimates were accomplished using a multiple trait animal model and the Derivative Free Restricted Maximum Likelihood (DFREML) method. In the IPP model, effects of month and year of birth were considered as fixed, while in the IDP, PL and DL models, month and year of kidding, beyond lactation order for PL and DL were considered as fixed; models included the direct genetic effect and error as random, and permanent environmental random effect for IDP, PL and DL. Heritabilities estimates were 0.21±0.01, 0.06±0.01, 0.12±0.05 and 0.03±0.01 for IPP, IDP, PL and DL, respectively for Saanen, and 0.49±0.04, 0.01±0.00, 0.10±0.03 and 0.07±0.02 for IPP, IDP, PL and DL, respectively for Anglo-nubian. The genetic correlations between IPP and IDP were 0.64±0.01 for Saanen and -0.71±0.27 for Anglo-nubian. The genetic correlations between PL and DL were 0.66±0.03 and 0.86±0.40 for Saanen and Anglo-nubian, respectively. Phenotypic selection can be used to improve IPP in Anglo-nubian population studied; however, for Saanen breed, other strategies, such as progeny test besides the performance test, they would be useful. Genetic trend for Anglo-nubian was observed for all traits studied; however, in Saanen, the genetic trend observed was only for PL.