GENETIC PARAMETERS OF HOLSTEIN CROSSBRED ON COMMERCIAL DAIRY FARMS IN CHITTAGONG, BANGLADESH

The study was conducted to estimate the genetic parameters of Holstein crossbred dairy cows in Chittagong, Bangladesh.  Study population consisted of animals from three genetic backgrounds: i) 50% Holstein × 50% Local (H × L); ii) 50% Holstein × 50% Shahiwal (H × SL); and iii) 25% Holstein × 25% Shahiwal × 50% Local (H × SL × L). Performances of 480 animals for age at first calving (AFC), postpartum heat period (PPHP), calving interval (CI), lactation length (LL) and lactation milk yield (LMY) form 1992 to 2005 were considered for analyses. Genetic parameters were estimated based on Restricted Maximum Likelihood Procedure (REML). The mean of calving interval was 442.59±7.78, 449.86±8.64 and 457.88±8.20 days in H × L, H × SL and H × SL × L crossbreds, respectively. The mean AFC and PPHP were the lowest for H × L cross. The average LMY was 1506.75±71.37, 1351.00±79.25 and 929.10±75.23 liters for H × L, H × SL and H × SL × L crossbreds, respectively. H × L genotype found to be the most efficient among the three genotypes. The overall heritability estimates in crossbreds were 0.10, 0.07, 0.05, 0.27 and 0.30 for AFC, PPHP, CI, LL and LMY, respectively. Genetic and phenotypic correlation coefficients among traits ranged from -0.14 to 0.30 and -0.16 to 0.31 for pooled data. Moderate to high heritability estimates along with high genetic and phenotypic correlations for LL and LMY elucidate that more potential exists for selecting these two traits simultaneously.