Evaluation of young crossbred bulls under field conditions

Abstract

This study aimed to evaluate the breeding value of crossbred bulls being used in Field Progeny Testing Programme at the Punjab Agricultural University (PAU), Ludiana, Punjab', in different sets and to rank them for first lactation 305 days milk yield. First lactation 305 days milk yield in crossbred cows averaged 2813±21.19 kg in field conditions. Effect of set, year and season ofcalving and age at first calving had non-significant effect on 305 days milk yield. The daughters' average 305 days milk yield varied from 2396 to 3 157 kg for different bulls. Best Linear Unbiased Prediction estimates ofthe sires ranged from 2 742 to 2 861 kg. The bulls inducted in set first and third had higher breeding value than those inducted in set second. Bulls within the set had minimum variation in first lactation milk yield while those between the sets had maximum variation. The accuracy of the breeding values ranged from 0.50 to 0.86. Bulls (25) offirst and third set had their breeding values exceeding overall mean (11) of 2812.70 kg while bulls inducted in second set were below average. Top 3 ranked bulls had superiority over herd average by 49.07, 48.70 and 48.68 kg and are being used under nominated mating.