Genetic and Environmental Parameters of Milkability Traits in Holstein Friesian Cows

The research was performed to determine the effect of non-genetic factors on milkability characteristics and to estimate genetic parameters and relationships among Milk Flow Rate (MFR), Milking Time (MT) and milk yields of Holstein Friesian cows reared in Eastern Region of Turkey. The data used in this study consisted of 1267 observations of MT and MFR on 177 lactations of 91 Holstein Friesian cows. The least squares means for MFR, MT and Total Test Day Milk Yield (TTDMY) were 1.049 kg min(-1), 5.83 min and 12.31 kg, respectively. Parity, stage of lactation and calving season affected (p<0.01) on the MFR, MT and TTDMY. Multiparous cows had higher MT and TTDMY (p<0.01) than primiparous cows. Calving season affected (p<0.01) on MT, MFR and TTDMY. The heritability coefficients for MFR, MT and TTDMY were 0.21, 0.23 and 0.23, respectively. The positive genetic correlations of MFR with TTDMY, actual milk yield and 305 days milk yield were 0.62, 0.49 and 0.48, respectively, while genetic correlations between MT and TTDMY, actual milk yield and 305 days milk yield were 0.20, 0.28, 0.34, respectively. Phenotypic and genetic correlations between MFR and MT were -0.49 and -0.63, respectively.