Estimation of Genetic Parameters of Reproductive and Milk Yield Traits Using Multiple-Trait Animal Model in Holstein Under Subtropical Conditions

The present study was aimed at estimation of the genetic parameters and the effect of season and year of birth on performance traits of Holstein Friesian cattle maintained at Agricultural University Dairy Farm Peshawar, Pakistan from the period 1 999 to 2008. Genetic parameters for studied traits were estimated using multiple-trait animal model by DMU Software package with year and season of birth as fixed effects. The effect of year and season of birth was found significant on all the traits under study. Mean Puberty Age (PA), Age at First Calving (AFC) first lactation 305 Days Milk Yield (305 DMY) and Reproductive Efficiency (RE) were 794.32 +/- 45.35 days, 1172.27 +/- 79.65 days, 3553 +/- 423.26 kg and 62.50 +/- 3.56%, respectively. Heritability estimates of PA, AFC, RE and first lactation 305 DMY were 0.17, 0.11, 0.12 and 0.22, respectively. Genetic correlation of PA with AFC was highly positive (0.67) whereas, genetic and phenotypic correlation of RE with PA and AFC was moderately negative. Genetic correlations of 305 DMY was highly negative with AFC and RE and moderately negative with PA. In the present study, Holstein outperformed indigenous breeds in terms of performance and genetically inheritable potential under the prevailing subtropical conditions of Pakistan. RE parameter studied is useful indicator for moderately inheritable reproductive traits and should be considered in future studies using large dataset. Interestingly, the genetic parameters of holstein in. the present study were in. normal range but the production was markedly lower than other studies in the temperate environmental conditions.