Chang Lian-Ben, Chou Chih-Jen, Shiu Jia-Shian, Tu Po-An, Gao Shi-Xuan, Peng Shao-Yu, Wu Shinn-Chih
Department of Animal Science and Technology, National Taiwan University, No. 50, Lane 155, Sec. 3, Keelung Road, Taipei, 10672, Taiwan, Republic of China.
Institute of Biotechnology, National Taiwan University, No. 81, Chang-Xing St, Taipei, 10672, Taiwan, Republic of China.
Trop Anim Health Prod. 2017 Aug;49(6):1157-1162. doi: 10.1007/s11250-017-1311-y. Epub 2017 May 20.
Our aim was to investigate insemination techniques in order to improve pregnancy rates of artificial insemination (AI) using sex-sorted semen (sexed AI) in cattle in tropical and subtropical (T/ST) regions. In T/ST regions, the pregnancy rates by sexed AI are reportedly the lowest in the hottest months of the year, with less than 15% in cows and 35-40% in heifers (PMID 24048822). We compared sexed AI by depositing the semen into the uterine body (UB-AI, n = 12) versus the unilateral uterine horn (UUH-AI, n = 14) of pre-ovulation heifers. The ovary and follicle were assessed by rectal ultrasound before AI. After insemination, pregnancy was determined by ultrasound at approximately 40 days and approximately 70 days. In the present study, we demonstrated that high pregnancy rates (>70%) by sexed AI in the hottest season in a subtropical region such as Taiwan can be achieved when heifers with pre-ovulation follicles are used. The overall pregnancy rates were 54% higher in the UUH-AI (71%) group than in the UB-AI (42%) group (P = 0.06), examined on approximately 40 days post-sexed AI. Surprisingly, however, the pregnancy outcome appeared to be higher in the hot season (62%) than in the cool season (46%) although this difference was not statistically significant. Based on the present study, we recommend that cattle breeders perform UUH-AI using sex-sorted semen for heifers with pre-ovulation follicles in order to achieve satisfactory pregnancy outcome in the hot seasons in T/ST regions.
我们的目的是研究授精技术，以提高热带和亚热带（T/ST）地区牛使用性别分选精液进行人工授精（AI）的妊娠率。在T/ST地区，据报道，在一年中最热的月份，性别分选AI的妊娠率最低，母牛低于15%，小母牛为35 - 40%（ PMID 24048822）。我们比较了将精液注入排卵前小母牛子宫体（UB - AI，n = 12）与单侧子宫角（UUH - AI，n = 14）的性别分选AI。在AI前通过直肠超声评估卵巢和卵泡。授精后，在大约40天和大约70天时通过超声确定妊娠情况。在本研究中，我们证明，在亚热带地区如台湾的最热季节，当使用有排卵前卵泡的小母牛时，性别分选AI可实现高妊娠率（>70%）。在性别分选AI后约40天检查时，UUH - AI组（71%）的总体妊娠率比UB - AI组（42%）高54%（P = 0.06）。然而，令人惊讶的是，尽管这种差异无统计学意义，但热季（62%）的妊娠结局似乎高于冷季（46%）。基于本研究，我们建议养牛者对有排卵前卵泡的小母牛使用性别分选精液进行UUH - AI，以便在T/ST地区的热季获得满意的妊娠结局。
