Evaluation of genetic relationship and inbreeding Effects on performance traits in holsteins friesian Herd at holeta bull dam farm, holeta, ethiopia

Abstract

This study was conducted on 8,527 Holstein Friesian cows born to 242 sires from seven origins and 1430 dams that calved between 1974 and 2006, archived for 32 years, with the objectives of evaluating the relationship and inbreeding, the inbreeding effects on the performances, and proposing the future mating strategy. The relationship among the small herd of Holstein Friesian dairy cattle at the Holeta Bull Dam farm was estimated by the RelaX2 software package. The traits considered in this study were birth weight (BWT), age at first calving (AFC), calving interval (CI), days open (DO), number of services per conception (NSC), lactation milk yield (LMY), lactation length (LL), and 305 days milk yield (305-dMY). The least squares mean of non-genetic factors affecting these traits were analyzed by fitting GLM procedures of SAS version 9.3 (2011). The genetic parameters and breeding values for BWT, reproductive, and milk production traits were estimated using the ASReml statistical package. The univariate analysis was undertaken for each trait for estimation of heritability (h 2 ±SE), repeatability (r±SE), and estimated breeding values (EBV), whereas genetic and phenotypic correlations were estimated using bivariate analysis