R.S.PandaySujit Kumar Kundu2024-07-152024-07-152001https://krishikosh.egranth.ac.in/handle/1/58102119891)Significant effect of period on different economic traits and better performance during 1995-2000 suggested that managemental practices of the farm in recent years have improved over the past. (2) Most of the earlier components of lactation such as initial milk yield, peak yield, days to attain peak yield, total yield up to peak and rate of increase up to peak indicated that first calvers are unable to express their genetic potentials fully as compared to second and third calvers. (3) Season of calving did not influence the economic traits, indicating that the traits under study remain unaffected by seasonal variability. (4) Phenotypic correlations of early components of lactations such as initial milk yield, peak yield, days to attain peak yield, total yield up to peak, days to attain peak yield and rate of increase up to peak with lactation yield indicated that lactation yield could be judged from early components of lactations effectively. (5) No definite patterns in genetic and phenotypic trends was observed in this study is indicative of large magnitude of environmental variations over the years. (6) Estimates of expected breeding value suggested that regular progeny testing of sires should be done and only progeny tested sires should be encouraged for semen bank.EnglishThesis