Estimates of genetic parameters for milk and milk constituent’s yield traits in Sahiwal cattle

Abstract

The objective of present study was to estimate genetic and phenotypic parameters of first lactation milk and milk constituent’s yield traits in Sahiwal cattle. Data on 363 first lactation milk and milk constituents records of Sahiwal cattle sired by 48 sires, spread over a period of 25 years from 1989-2013 maintained at Animal Genetics and Breeding Division, ICAR-NDRI, Karnal, were analyzed to estimate genetic and phenotypic parameters of first lactation 305 days or less milk yield (FL305DMY), first lactation 305 days or less fat yield (FL305DFY), first lactation 305 days or less solid not fat yield (FL305DSNFY) and first lactation 305 days or less total solid yield (FL305DTSY). Effect of sire, season of calving and age at first calving (AFC) was found to be non-significant on all the traits. Period of calving had significant effect on all traits except FL305DMY Effect of first service period (FSP) as a covariable was found to be highly significant on all the traits. Heritability estimates of FL305DMY, FL305DFY, FL305DSNFY and FL305DTSY were found to be 0.185, 0.178, 0.195 and 0.189, respectively. Genetic correlation of FL305DMY with FL305DFY was 0.99 ± 0.01. Phenotypic correlations of first lactation 305 days or less milk yield with FL305DFY, FL305DSNFY and FL305DTSY were positive (0.99±0.01) and statistically highly significant (p<0.01). Moderate estimates of heritability and high genetic correlation between milk and milk constituent’s yield traits suggested scope of improvement of Sahiwal cattle through correlated response in these traits or correlations of FL305DMY with milk constituents’ yield traits implied that selection based on FL305DMY would result in correlated response in milk constituents yield traits and hence need not to be considered separately for their improvement.