Prediction of lactation yield from test day milk yield and peak yield in Kankrej cows.

摘要

Complete record keeping is very difficult due to time and labour consumed, transfer, sale and death of animals. Test day and peak milk yield have high relationship with lactation yield. Therefore, the present study was carried out to predict the lactation yield based on test day and peak yield. Test day milk record was taken at 30 days interval from records of 7 lactations belonging to 300 Kankrej cows maintained at Livestock Research Station, Gujarat Agricultural University, Sardarkrushinagar. The simple regression analysis using TDYs and PY revealed that peak yield alone could predict the lactation yield to the 49% of accuracy. Prediction of LY based on 125th, 155th, 185th and 215th day would be quite useful and reliable with more than 66% accuracy. The multiple regression equation indicated that R2 values showed increasing trend when more number of test day milk yields were included in prediction. The best suggested equation with 78% accuracy is: Lv=-118.62+81.12 PY+85.20 TDY₁₅₅+TDY₁₈₅.