Effect of genetic and non-genetic factors on age at first calving in Sahiwal cattle

The present study was conducted on Sahiwal cows maintained at Uttar Pradesh Livestock-cum-Agriculture Farm, Chak Ganjaria, Lucknow. A total of 1194 records on age at first calving (AFC) spanning over a period of 57 years (1949 to 2006) were subjected to least squares analysis using suitable statistical model considering sire as random while period and season as fixed effects. The least squares mean of AFC was estimated to be 1251.77± 22.15 days. The least squares analysis revealed significant effect (P ≤ 0.01) of sire and period. However, the effect of season was found to be non-significant. The heritability estimate of age at first calving was found to be 0.159. The genetic, phenotypic and environmental trend for AFC were-3.31, 32.78 and 36.09 respectively. It was concluded from the present findings that selection of sire may be practiced for genetic improvement of this trait and ameliorative managemental practices should be employed to improve upon the trait i.e. age at first calving.