Effect of genetic and non genetic factors on first lactation traits in Gir cows

Abstract

A total record of 113 Gir individuals spread over a period of 18 years from 1995 to 2012, were analyzed to estimate the effect of genetic and non genetic factors on first lactation period, first lactation milk yield and first dry period. The overall means for first lactation period (FLP), first lactation milk yield (FLMY) and first dry period (FDP), were 343.58± 10.37 days, 1664.95± 280.72 litres and 177.29± 10.59 days respectively. The heritability estimates for FLP, FLMY and FDP were 0.168± 0.238, 0.112± 0.252 and 0.419± 0.234 respectively. The genetic correlation between FLP and FLMY was positive and significant, while it was low and negative between FLP and FDP. The genetic correlation between FLMY and FDP was positive and highly significant. The phenotypic correlations between all traits were high and positive.