International Journal of Agriculture Extension and Social Development

author(s)
Garima Choudhary, U Pannu, and GC Gahlot

abstract
This study utilized performance data from 91 cows, offspring of 10 sires, observed over an 11-year period (2006 to 2016) at LRS, Beechwal, Bikaner, to assess sire performance based on first lactation traits. The traits analyzed included age at first calving, first lactation milk yield, first lactation period, first dry period, first calving interval, and first service period. Breeding values were estimated using the Least Squares Method (LSM). The results indicated substantial genetic variation among sires for all first lactation traits. Additionally, the rankings of the top sires varied when evaluated using LSM, suggesting heterogeneous performance across traits. These findings underscore the diverse genetic profiles among sires under study for these specific traits.