摘要 : The present research was carried out to determine the effect of non-genetic factors on first lactation 305 days and lifetime milk yield of Sahiwal cattle. Data were collected on 392 cows maintained atNDRI, Karnal herd for first la... 展开 The present research was carried out to determine the effect of non-genetic factors on first lactation 305 days and lifetime milk yield of Sahiwal cattle. Data were collected on 392 cows maintained atNDRI, Karnal herd for first lactation 305 days milkyield and on 282 cows for lifetime production, over a period of 31 years (1986-2017). The traits were subjected to least squares analysis using Harvey (model 1) considering season of calving, period of calving and age at first calving as fixed effects.The overall least squares mean for first lactation 305 days milk yield and lifetime milk yield were found to be 1898.95 ±50.26 and 7241.47 ±411.18 Kg respectively. The effect of season of calving and age at first calving was found to be non- significant on first lactation 305 days milk yield whereas the effect of period of calving was significantly affecting first lactation 305 days milk yield. The effect of season of calving was non-significant on lifetime milk yield also. Age at first calving and period of calving had a highly significant effect on life time milk yield of Sahiwal cattle. Hence, 4e data needs to be adjusted for all the significant non-genetic factors so that the data may be used further for genetic analysis. 收起