Assessment of genetic gain and its simulation for performance traits in Sahiwal cattle

Abstract

The study was conducted to estimate the expected genetic gain (∆G) 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 ∆G 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, ∆G 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 ∆G in 305DMY decreased by 14% and increased by 8%, respectively. A similar trend in ∆G was found when simulating the number of progenies/sire by 50% in WA and CFI. Expected ∆G was also assessed by increasing the number of progenies per sire gradually from 6 to 18. Initially, there was a noticeable increase in ∆G upon increasing the number of progenies/sire gradually from 6 to 11, but with a further increase in the number of progenies/sire, ∆G increased only gradually and the magnitude was found to be low.