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 < .05). Overall, dairy (X-sexed, 61.9% and unsexed, 62.0%) cows had greater conception rates on Day 35 compared to beef (X-sexed, 56.0% and unsexed, 52.2%) cows (p < .05). Concurrently, on Day 95, overall conception rates in dairy (X-sexed, 41.4% and unsexed, 48.5%) cows were greater than beef (X-sexed, 38.0% and unsexed, 37.0%) cows (p < .05). Pregnancy/embryo losses between Days 35 and 65 in dairy (X-sexed, 33.3% and unsexed, 18.2%) cows and beef (X-sexed, 28.6% and unsexed, 29.2%) cows were recorded (p < .05). Dairy (X-sexed, 7.7% and unsexed, 8.3%) cows had higher incidence of pregnancy losses between Days 66 and 95 when compared to beef (X-sexed, 5.0% and unsexed, 0.0%) cows (p < .05). Oestrous expression and conception rates in dairy and beef cows were satisfactory. Advanced reproductive biotechnologies can successfully utilize gender-ablated semen in organized emerging cattle farming systems.
摘要：
这项研究的目的是比较TAI后发情同步表达和受胎率与乳牛和肉牛中冷冻解冻的X性别或无性别精液。对于这项研究，将227头母牛（乳制品；n=130和牛肉；n=97）分配给9天的Ovsynch受控阴道内药物释放（CIDR）方案。使用来自八个父亲的X性别或无性别精液对所有母牛进行定时人工授精（TAI）。每种精液类型都是从四个父亲[两个乳制品（荷斯坦·弗里斯亚）和两个牛肉（安格斯）]中获得的。在TAI后第35、65和95天通过经直肠超声检查和手触诊进行妊娠检测。奶牛(85.3%)发情反应比例高于肉牛(65.0%)(p<0.05)。总的来说,与牛肉（X性别；56.0％和无性别；52.2％）奶牛相比，第35天的奶牛受孕率更高（p<0.05）。同时,在第95天，奶牛（X性别；41.4％和无性别；48.5％）的总体受胎率高于牛肉（X性别；38.0％和无性别；37.0％）的奶牛（p<0.05）。在第35天和第65天之间,记录了奶牛(X-性别;33.3%和无性别;18.2%)和牛肉(X-性别;28.6%和无性别;29.2%)的妊娠/胚胎损失(p<0.05)。与牛肉（X性别；5.0％和无性别；0.0％）奶牛相比，乳牛（X性别；7.7％和无性别；8.3％）在第66天和95天之间的妊娠半胱氨酸损失发生率更高（p<0.05）。奶牛和肉牛的发情反应和受胎率令人满意。先进的生殖生物技术可以在有组织的新兴牛养殖系统中成功利用性别消融的精液。
