Genetic relationship of age and weight at first calving with first lactation milk yield in Khuzestani buffaloes

Abstract

Data from 815 normal first lactation records of Khuzestani buffaloes belonging to animal production research institute in province of Khuzestan, were analyzed. Least-squares means of first 305-day milk yield (305 MY), first lactation period (LP), age st first calving (AFC), and weight at first calving (WFC) were 1081±37 kg, 252±7 day, 38.20±0.29 month, and 375±2.0 kg respectively. Least-squares analysis of variance revealed that month of calving had a significant effect on 305 MY and LP (P&lt.01). The year of calving had a significant effect on all the 4 traits. AFC had a significant effect only on WFC, while the WFC effect was significant on 305 MY, LP, and AFC. Heritability estimates were 0.18±0.07,0.20±0.09 ,0.59±0.11 and 0.01±0.08 for 305 MY, LP, AFC and WFC respectively. The genetic and phenotypic correlations between 305 MY and LP were 1.00±0.90 and 0.89, respectively.