Wilmink lactation curve model for prediction of monthly test day milk yields and first lactation milk yield in crossbred cattle of Kerala

The milk yield information of progenies of test bulls were collected from the history sheets and milk record registers of ICAR-Field Progeny Testing Scheme, Kerala. A total of 10 monthly test-day milk yield records (20thday, 50th day,…, 290th day) were taken at an interval of 30 days. Total of 8020 first lactation MTDMYs records of crossbred cattle of Kerala was used to estimate lactation curve parameters for the Wilmink function lactation curve model. Average first lactation MTDMYs predicted with maximum accuracy (R2= 86.45%), AIC (-58059.79), BIC (-9656.57) and (RMSE = 0.009949 kg). was obtained with Wilmink function. Average first lactation milk yield and predicted FLMY was 2507.87 kg and 2529.43 kg, respectively. This property can be useful in case of incomplete records because in field level more chances for missing data due to certain expected conditions. Modelling of lactation curve is an important tool in designing appropriate breeding and management strategies to achieve genetic improvement.