Prediction of 305 days first lactation milk yield from fortnightly test and part yields

Abstract

Data on 453 Surti buffaloes maintained at “Network Project on Surti buffaloes’’ Livestock Research Station, Vallabhnagar, Udaipur were used to predict 305 days first lactation milk yield (305 FLMY) from fortnightly test day milk yield (systematic and stratified random sampling) and part yields. The 10^th and 11^th fortnight gave the highest accuracies of fitting when fortnightly systematic and stratified random sampling using single test record were used. The 10^th fortnight part yield also gave the highest accuracy (62.10%) of prediction of 305 days first lactation by regression method. When two fortnightly test records and part yields were taken, the best multiple regression equations were found to be those utilizing 4^th and 10^th fortnightly test records under systematic sampling, 4^th and 11^th fortnightly test records under stratified random sampling and 6^th and 10^th fortnightly part yield; the accuracy of prediction being 69.70,69.70 and 75.50% respectively. When 3 tests and part records were considered, the best equations involved 4^th,10^th and 14^th fortnightly test records under systematic sampling, 4^th, 11^th and 14^th fortnightly test records under stratified and 6^th,10^th and 14^th fortnightly part yield; their accuracy of prediction being 77.50, 77.20 and 85.50% respectively. When more number of test and part records were considered as independent variable there was increase in accuracy of prediction but with slow rate.