Utilization of half-sibs information to increase the accuracy of young bull selection

Abstract

The present study was conducted to compare the breeding values of bulls in different sire evaluation methods and to explore the possibility of information on dam's yield and half-sibs in sire evaluation methods utilizing the data from Progeny Testing Scheme of KLD Board. Total 25 bulls, which had minimum of fifteen progeny and ten half-sibs were used. Out of 1212 records, progeny and half-sibs had 847 and 365 respectively distributed in 43 centres. The overall mean of first Lactation milk yield (FLMY) of progenies, half-sibs and both together were 2389.0 ± 23.46, 2131.0 ± 36.34 and 2311.3 ± 20.00, kg, respectively. Different centres and years of calving exerted significant effect on FLMY but season and age at first calving did not influence FLMY. Heritability estimate of FLMY was found to be 0.221 ± 0.077. Estimated sire merit (ESM) of bulls were estimated using ten indices viz. based on performance of dam (M), based on performance of paternal half-sibs (HS), based on performance of dam and paternal half-sibs (M+HS), based performance of dam, paternal half-sibs and progeny (M+HS+P), simple daughter average (SDA), contemporary comparison (CC), least squares (LS), KLD Board method, BLUP without considering relationship of sires (BLUP-l) liand BLUP considering relationship of sires (BLUP-2). The range ofESM were '+62.8745 to +396.8055, -157.169 to +287.358, -24.591 to +316.516, -193.877 to + 307.601, kg for M, HS, M+HS and M+HS+P respectively. The SDA and ESM of CC ranges were 2153.8 to 2663.2 and -1628.80 to 1876.58, kg respectively whereas CC index ranged from -258.79 to +406.74, kg. The ESM of LS, KLD Board, BLUP-I and BLUP-2 ranges were -450.92 to +567.69, _ 111.83 to +513.78, -329.8 to +370 and -332.8 to +362.6, kg, respectively. Rankings of sires by different methods were not the same but ranking by SDA, LS and KLD Board method was almost similar with rank and product-moment

correlations around one. Ranking by CC, BLUP-l and BLUP-2 were similar with very high rank and product-moment correlations. The average standard error (SE) of SDA, LS, KLD Board, BLUP-l and BLUP- 2 were estimated. BLUP-J followed by BLUP-2 had lowest SE and SDA had the highest. The results are suggestive of opting for BLUP procedures for sire evaluation in Kerala. Additional information on dam and half-sibs did not have much advantage if more progeny records are available for sire evaluation.