Application of gender-ablated semen during timed artificial insemination following oestrous synchronization in dairy and beef cows

Abstract

The objectives of this study were to compare oestrous synchronization expression and conception rate following timed artificial insemination (TAI) with frozen–thawed X-sexed or unsexed semen in dairy and beef cows. For this study, 227 cows (dairy, n = 130 and beef, n = 97) were assigned to a 9-day Ovsynch + controlled intravaginal drug release (CIDR) protocol. All cows were TAI using X-sexed or unsexed semen from 8 sires. Each semen type was obtained from 4 sires [2 dairy (Holstein Friesian) and 2 beef (Angus)]. Pregnancy detection was performed on Days 35, 65 and 95 following TAI by transrectal ultrasonography and hand palpation. The proportion of oestrus expression was higher in dairy (85.3%) cows compared with beef (65.0%) cows (p