Prediction of lactation milk yield from test day records in Murrah buffaloes

Abstract

The data pertaining to 326 Murrah buffaloes, pregnancy of 48 bulls calved during period from 1987 to 2006 maintained at the University were considered for the present study. The index involving test day records from first to seventh had an accuracy of selection of 0.593, which is greater than accuracy of direct selection and thereafter, there was trivial increase in accuracy by adding subsequent test day records. Accuracy of bimonthly test day recording is good as accuracy for lactation yield and accuracy for monthly records. The accuracy of selection (rIH) for odd test day records (TD1 + TD2 + TD3 + TD4 + TD5 + TD7 + TD9) was 0.686 and for even test day records (TD2 + TD4 + TD6 + TD8 + TD10) was 0.652. Both the alternate test day records of first lactation had higher accuracy of selection than the accuracy of direct selection (0.566). Therefore, the bimonthly recording of test day could be better alternative for selection of bulls as it saves cost of recording. The coefficient of determination (R2) was maximum (39.89%) for TD8 among all ten prediction equations having only one variable and minimum for TD2 (4.69%). The equation having the combination of test day recording third, seventh, eight, and tenth is recommended for prediction of first lactation milk yield as it has 56.97% value for R2 and after that there was slight increase in the value of coefficient of determination.