Studies on genetic evaluation of first lactation traits in crossbred cattle

Abstract

The present investigation was carried on crossbred cattle maintained at Instructional Dairy Farm, Nagla of G.B. Pant University of Agriculture and Technology, Pantnagar. The study was conducted on 700 crossbred cattle, the progeny of 68 sires which were born over a period of 28 years from 1990-2017. The overall least squares means along with standard errors of AFC, FLMY, FLP, FDP, FCI, FSP and FL305DMY were observed as 1186.45±8.66 days, 2846.16±46.92 kg, 326.51±3.09 days, 124.29±3.67 days, 450.80±4.5 days, 261.34±1.77 days and 2631.07±35.68 kg, respectively. The effect due to sire was found significant on AFC, FLMY, FCI and FL305DMY. The effect of the genetic group was non-significant on all the traits under study. The significant effect of season of calving was found on AFC, FLMY, FDP, FSP and FL305DMYwhile non-significant effect of season of calving on FLP and FCI was observed. The effect of the period of calving was observed significant on FLMY and FL305DMY, however, a non-significant effect of the period of calving was observed on AFC, FLP, FDP, FCI and. FSP. The heritability estimates for AFC, FLMY, FLP, FDP, FCI, FSP and FL305DMY were observed as 0.429±0.127, 0.267±0.110, 0.078± 0.087, 0.048±0.083, 0.096±0.089, 0.114±0.09 and 0.273±0.110, respectively. The results of the present study showed that most of the variations in the traits were due to non-additive genetic and environmental variances. Therefore, improvement in these traits can be made through better managemental practices at the farm. Keywords: First lactation milk yield, Least square means, Heritability, Crossbred cattle.