Parámetros genéticos para caracteres productivos y reproductivos en Holstein y Jersey colombiano

Abstract

The objective of this study was to estimate genetic and phenotypic parameters in milk production and reproduction traits in Holstein and Jersey from Antioquia, Colombia. The information was obtained from 85 Holstein dairy herds and 7 Jersey dairy herds. The milk production traits evaluated were: milk yield (PL), protein percentage (PP), fat percentage (PG) and somatic cell score (SCS) and the reproduction traits evaluated were: calving interval (IEP), days open (DA), number of services per conception (NSC) and conception rate (TC). The (co) variance components, genetic and phenotypic parameters were estimated by using univariate and bivariate linear mixed models and the solutions of the mixed model equations were obtained through derivative-free restricted maximum likelihood method. The heritabilities obtained for milk production traits ranged from 0.22 to 0.35, except for SCS that were low (h2<0.11) and for reproduction traits ranged between 0.03 and 0.15. The highest genetic correlations for Holstein were: rgIEPxPL= 0.77, rgIEPxPP= 0.61, rgIEPxPL= 0.77 and rgDAxSCS= 0.73 and for Jersey were: rgIEPxPP= 0.56, rgIEPxSCS= 0.49, rgTCxPG= –0.52 and rgTCxSCS= –0.72. Phenotypic correlations were low in all cases, ranged from –0.17 to 0.16. Milk production traits are more heritable than reproduction traits. However, genetic correlations suggest that it is favorable to construct selection indices from these traits to gain more genetic progress but balanced in their productive and reproductive components.