ESTIMATION OF GENETIC AND PHENOTYPIC TRENDS FOR FIRST LACTATION TRAITS IN MURRAH BUFFALOS

The aim of study was to estimate genetic and phenotypic trends in firs t lactation traits, viz. age at first calving (AFC). first lactation m ilk yield (FLMY), first lactation length (FLL) and first calving inter val(FCI) in Murrah herds maintained under 3 Uttar Pradesh Government L ivestock and 4 military farms. Genetic trends were estimated from regr ession of weighted averages of sires' transmitting abilities for each year on the year. Best linear unbiased prediction (BLUP) procedure was used to obtain the estimates of transmitting abilities of sires. The annual phenotypic trends at different farms for AFC ranged from -3.12 +/- 1.67 to 2.37 +/- 1.91 days. Genetic trend of -1.29 +/- 0.64 days/y ear for AFC at Lucknow military dairy farm was in desirable direction and significantly different from zero. Phenotypic trends in FLMY were not different from zero at all farms except Government Livestock Farm at Mathura. Annual phenotypic (7.04 +/- 1.26 days) and genetic (1.03 /- 0.38 days) trends in FLL were significantly different from zero at Government Livestock Farm, Babugarh. Genetic trends for FCI at all far ms were not significantly different from zero. Estimates of genetic an d phenotypic trends suggest that these farms require suitable breeding schemes for bringing genetic improvement.