Inheritance pattern of first lactation production traits in Murrah buffalo

Performance records pertaining to 707 first lactation Murrah buffaloes maintained at National Dairy Research Institute (NDRI), Karnal were analyzed by least-squares method. Heritability, genotypic and phenotypic correction of production traits were estimated with the help of paternal half-sib correlation method. The least squares means of production traits were 1754.79kg, 4.28kg, 7.95kg, 8.10kg, 7.93kg, 7.57kg, 7.05kg, 6.60kg, 6.03kg, 5.33kg, 4.79kg and 4.19kg for first lactation 305 days milk (FL305DMY) and 11 monthly test day milk records (TDMY) namely, 6th test day milk yield followed by 35, 65, 95, 125, 155, 185, 215, 245, 175 and 305 test day milk yield. Period of calving of animals had significant (p <= 0.01) effect however, season of calving and age at first calving had non-significant effect on first lactation 305 days milk yield. Except TD1, all other monthly TDMY were found to be influenced significantly due to period of calving. Only TD2, TD3 and TD4 milk yields were influenced significantly due to the variation of age at first calving of Murrah buffaloes. The heritability of studied traits had low to moderate estimates. The heritability for first lactation 305-days or less milk yield obtained was 0.24 and first lactation monthly test day milk yield varied between 0.04 in TD11 MY and 0.21 in TD4 MY. The genetic correlations for all traits were moderate to high except for TD1 with all other test day records. It was observed that TD5 MY (125th day milk yield) had the highest phenotypic correlation with first lactation 305-days or less milk yield in Murrah buffaloes. The results of the present study suggests that test day yields could be used as the selection criteria in Murrah buffaloes.