Relationship between sires' estimated breeding values for first lactation and lifetime traits in Hariana cattle

مجهول. Best linear unbiased prediction (BLUP) procedure was used to obtain the estimates of sires' breeding values from performance records of 601 daughters of 28 sires of Hariana cattle maintained during 1976 to 1996 at the Government Livestock Farm, Hisar, Haryana. First lactation traits included were age at first calving (AFC), lactation milk yield (FLMY), lactation length (LL), peak yield (PY), service period (SP), dry period (DP) and calving interval (CI): and lifetime traits were herd life (HL), lifetime milk yield (LTMY), productive life (PL), no. of days in milk (ND) and milk yield/day of productive life (MY/PL). Model for BLUP included year-season of calving and sire genetic group as fixed effects and sire within sire genetic group as random effect. The estimated breeding values (EBV's) showed large variation between sires for first lactation traits whereas, the EBV's of sires for lifetime traits showed less variation. The EBV's of sires for AFC had negative product moment correlations with FLMY, LL, PY and DP. The EBV's of sires for FLMY had significant positive product moment correlations with LL and PY but negative with DP. The product moment correlations among sires' estimated breeding values for HL, LTMY, PL and ND were high and positive (0.67 to 0.93). Product moment correlations of sires' EBV's for FLMY and LL with EBV's for HL, LTMY, PL and ND were significant and positive (0.53 to 0.83). Rank correlations among EBV's of sires indicated that all sires would not rank same for first lactation and lifetime performance traits. However, the ranks of sire for different traits revealed that 4-5% of top sires almost had similar rank for first lactation and lifetime traits. Results suggest that to improve lifetime productivity major culling of bulls to breed cows should be done on the basis of their daughter's first lactation milk yield.