Use of Lactation Curve Models for Prediction of Milk Yield in Sahiwal Cattle

A study was carried out on of 25499 weekly test day milk yield records of first lactation pertaining to 593 Sahiwal cows spread over 49 years located at National Dairy Research Institute, Karnal, India. The relative efficiency of three lactation curve models via. quadratic model, gamma type function and mixed log function were compared. Mixed log function described the best fit with highest coefficient of determination (97.9%) with root mean squares error (RMSE) of 0.025 kg which is followed by gamma type function. Least coefficient of determination (77.8%) was observed in quadratic model with maximum (0.081) RMSE. The peak yield of 8.08 kg in 8th week of lactation was observed by mixed log function. The predicted first lactation 305 day milk yields by quadratic model, gamma type function and mixed log function were 1993.23± 42.09, 1991.51± 40.38 and 1993.23± 42.10 kg, respectively