Prediction of Standard lactation Milk Yield from Completed Lactations of Longer Duration in Cattle and Buffaloes

The aim of this study was to develop a procedure to adjust lactations of longer duration to a standard such as 305-days when standard lactation milk yield for such lactations could not be recorded. For Sahiwal cattle and Nili-Ravi buffaloes, information on completed lactations for duration of more than 305-days was used for 3054 and 3927 lactations, respectively. Final regression equations to predict standard lactation milk yield (305-day milk yield) (SLMY) from completed lactation milk yield (CLMY) and lactation length (LL) were obtained using multiple regression analysis. Species Regression equations R^2 (%) VIF Sahiwal Cattle Predicted SLMY = 1239 + 0.967 (CLMY) - 3.80(LL) 96.5 0.035 Nili-Ravi Buffaloes Predicted SLMY = 1604 + 0.925 (CLMY) - 4.75 (LL) 96.1 0.039 Thus, standard lactation milk yield can be fairly adequately predicted from total milk yield of longer lactations and lactation length using linear regression technique both in Sahiwal cattle and Nili-Ravi buffaloes with reasonable accuracy.