Estimation of genetic and phenotypic trends from production efficiency traits in murrah buffaloes

Genetic and phenotypic trends were estimated for first lactation milk yield (FLY), first lactation peak yield (FPY), average yield per day of lactation (AYL), lactation milk yield per day of first calving interval (MCI) and lactation milk yield per day of age at second calving (MSC). Genetic trends for different traits were estimated by taking the regression of weighted average of sire's estimated breeding value (WAEBV) for each year on year. Phenotypic trends for each trait were calculated as linear regression of performance of population on year. Negative genetic and phenotypic trends were obtained over the years. But, the values were non-significant.