Genetic parameters for milk yield and reproductive traits in Honduran Holstein cattle

Abstract

The objective of this study was to estimate the (co)variance components and genetic parameters for milk yield (MY), calving-to-conception interval (CCI), number of services per conception (NSC) and calving interval (CI) of Honduran Holstein cows, by tting a bivariate animal model using Maximum Restricted Likelihood procedures. Model included the xed effects of, calving number, the contemporary calving group (farm-season-year of calving and the cow age as covariate). The estimated means and standard deviations for MY, CCI, NSC and CI were, 5098.60 ± 1564.32 kg, 168.27 ± 104.71 days, 2.46 ± 1.69 services, and 448.73 ± 109.16 days, respectively; and their estimated heritabilities were 0.21 ± 0.05, 0.03 ± 0.028, 0.02 ± 0.024 and 0.06 ± 0.04, respectively. The genetic correlations between MY305 and CCI, NSC and CI were positive and antagonist, with values of 0.64 ± 0.52, 0.99 ± 0.56, and 0.32 ± 0.24 respectively. Even though moderate to low heritability was estimated for MY, important genetic considering the systematic selection of MY; however, with a reduction in reproductive e ciency, if considered as the only selection criterion. By including reproductive traits and considering permanent environment effects into the breeding program, will yield a slow, but constant and permanent improvement over time.