Factors Affecting, Birth Weight, Age and Weight at First Calving in Sahiwal Cattle

A total of 354 records of Sahiwal individuals spread over a period of 24 years (1980–2003) were analyzed to estimate the effect of certain genetic and non-genetic factors on birth weight, age at first calving, and weight at first calving. The least squares means (LSMS) for birth weight (BW), age at first calving (AFC) and weight at first calving (WFC), were 20.41 ± 0.23 Kg, 1078.09 ± 21.12 days and 367.69 ± 4.48 Kg, respectively. The heritability estimates for birth weight (BW), age at first calving (AFC) and weight at first calving (WFC), were 0.20 ± 0.14, 0.041 ± 0.110 and 0.285 ± 0.156,respectively. The phenotypic correlation between birth weight and age at first calving was positive and highly significant. The correlation between age at first calving and weight at first calving was non-significant.