Rakshe, P.T.Yazdani, Ahmad R.2018-08-172018-08-171992http://krishikosh.egranth.ac.in/handle/1/5810065335The present study entitled, "Comparative performance of first lactational traits in Jersey X Red Sindhi and Friesian X Red Sindhi", was undertaken at the Agricultural College Dairy Farm, Pune. Data on fifty eight Red.Sindhi halfbred cows from 1974 to 1988 were collected and analysed to study the reproduction, production and prod uction efficiency traits. The least squares analysis (Harvey, 1966) was carried out to assess the influence of genetic group, period of calving and season of calving on said traits. Correlations between economically important traits were studied. Prediction equations were developed to predict full milk yield, 300 days milk yield, daily milk yield per 300 days, daily milk yield per lactation length and daily milk yield per calving interval. The least-squares means for age of first calving (days), full milk yield (kg), 300 days milk yield (kg), lactation length (days), calving interval (days), daily milk yield per 300 days (kg), daily milk yield per lactation length and daily milk yield per calving interval were 1059.05 (days), 2623.84 (kg), 2144.54 (kg), 360.71 (days), 380.27 (days), 7.22 (kg), 7.20 (kg) and 5.77 (kg) for FRS, these figures were 1007.99 (days), 2705.12 (kg), 2094.28(kg), 394.14 (days), 384.51 (days), 6.98 (kg), 6.89 (kg) and 5.70 (kg) for JRS. Period of calving exerted significant influence on age at first calving in FRS and DMY/300 days, DMY/LL and DMY/CI in JRS. Season of calving did not show significant influence on any trait under study. Both genotypes differed significantly for lactation length. In multiple regression of birth weight and age at first calving on full milk yield, 300 days milk yield, daily milk yield/300 days, daily milk yield/lactation length and daily milk yield/calving interval, all partial regression coefficients were non-significant in Friesian x Red Sindhi and Jersey x Red Sindhi. Accuracy of predictability of said traits was ranged from 5.00 to 51.00 per cent in both genotypes.ennullThesis