Estimates of sires' breeding values, and genetic and phenotypic trends for various economic traits in Murrah buffaloes

Best linear unbiased prediction (BLUP) procedures was used to obtain the estimates of sire's breeding values (EBV) from performance records of 561 daughters of 37 sires of Murrah buffaloes collected during 1943-72 at military dairy farm, Jabalpur. First lactation traits included in the study were age at carving (AFC), lactation milk yield (FLMY), lactation length (FLL), dry period (FDP) and calving interval (FCI); and lifetime traits wire number of lactations completed (NLC), herdlife (HL) and lifetime milk yield (LTMY). Model for BLUP included the season and year of calving and sire's genetic group as fixed effects and sire within sire genetic group as random effect. The annual genetic trend was obtained from regression of weighted average of sire's breeding values for each years. Linear regression of phenotypic means of years on year was taken as phenotypic trend. The EBV's showed large variation between sires for first lactation and lifetime traits. Rank correlations between first lactation and lifetime traits ranged between -0.84 and 0.83. Rank correlations among the EBV's of sire for different traits indicated that the sires ranked differently for first lactation and lifetime traits. The EBV's of sire for AFC and FLMY were negatively correlated with EBV's for lifetime production traits. The annual genetic trends for AFC, FLMY, FLL, FDP and FCI were -34.32+/-2.33 days, -14.43+/-2.04 kg, -0.52+/-0.21 days, 4.27+/-0.19 days and 3.92+/-0.39 days respectively, The corresponding annual phenotypic trends for these traits were 23.27+/-2.22 days, 1.24+/-3.27 kg, 1.03+/-0.62 days, 1.71+/-0.89 days and -0.86+/-1.05 days respectively. Relationship between the sire's breeding values for FLMY with their dam's first lactation or the best lactation milk yield were low. Results suggested that selection of bulls based on dam's milk production is not a suitable selection criterion for bringing genetic improvement in the herd. Therefore major selection of bulls should be done on the basis of first lactation milk yield of their daughters.