Genetic and Environmental Correlation of Age at First Calving with Various Production Traits in Gir Cattle

Abstract

The main objective of this study was to estimate genetic and environmental correlations between Age at First Calving and various production traits in Gir cattle. The production traits studied were: Standard Lactation Milk Yield, Peak Milk Yield, Lactation Length and Dry Period. The production records on 345 Gir cows with 1257 lactations sired by 52 bulls, maintained at Cattle Breeding Farm, Junagadh, Gujarat, over 24 years (1987–2010) were studied. The analysis revealed positive environmental correlation of Age at First Calving with Lactation Length (0.224 ± 0.234) and Dry Period (0.039 ± 0.195), while negative environmental correlation of Age at First Calving with Standard Lactation Milk Yield (-0.194 ± 0.178) and Peak Milk Yield (-0.070 ± 0.200). Genetic correlation of Age at First Calving with Standard Lactation Milk Yield (0.006 ± 0.178), Peak Milk Yield (0.069 ± 0.200), Lactation Length (0.752 ± 0.234) and Dry Period (0.058 ± 0.195) were found during this study, in which genetic correlation between Age at First Calving and Lactation Length was found highly significant. These indicated that selection for Age at First Calving would not reflect upon Standard Lactation Milk Yield and Peak Milk Yield.