Turkish Journal of Veterinary & Animal Sciences




The study was conducted to estimate the expected genetic gain (ΔG) for first lactation performance traits in Sahiwal cattle as a result of direct selection of animals maintained at the ICAR-National Dairy Research Institute in India. Data pertaining to 305-day milk yield (305DMY), wet average (WA), and calving to first insemination interval (CFI) of the animals considering 13 counts of progenies/ sire were initially analyzed. The ΔG through direct selection was 43.68 kg/year, 0.13 kg/year, and 1.68 days/year for 305DMY, WA, and CFI, which was 1.97%, 1.65%, and 2.02% of herd average, respectively. In addition, ΔG was estimated by simulating the number of progenies/sire by 50%, i.e. by 6 and 18. Upon simulation of the number of progenies/sire, the ΔG in 305DMY decreased by 14% and increased by 8%, respectively. A similar trend in ΔG was found when simulating the number of progenies/sire by 50% in WA and CFI. Expected ΔG was also assessed by increasing the number of progenies per sire gradually from 6 to 18. Initially, there was a noticeable increase in ΔG upon increasing the number of progenies/sire gradually from 6 to 11, but with a further increase in the number of progenies/sire, ΔG increased only gradually and the magnitude was found to be low.

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