Department of Obstetrics, Gynaecology and Reproduction, Swine Reproduction Research Unit, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Department of Technology of Farm Management, Faculty of Agro-Industry, Panyapiwat Institute of Management, Bangkok, Thailand.
Theriogenology. 2020 Jan 15;142:54-61. doi: 10.1016/j.theriogenology.2019.09.032. Epub 2019 Sep 20.
We evaluated the reproductive performance of sows after single fixed-time AI under a tropical climate and investigated the influences of season and insemination technique on the efficacy of single fixed-time AI. After weaning, the sows were divided into CONTROL (n = 212) and FIXED-TIME (n = 212) groups. Sows in the CONTROL group were inseminated at 12 and 36 h after the onset of oestrus, while sows in the FIXED-TIME group were administered 10 μg of GnRH at 72 h after weaning and were inseminated 32 h later. Reproductive performance parameters, including total born, born alive, mummified foetuses and stillborn piglets per litter, piglet birth weight, variation of piglet birth weight within litter, regular return-to-oestrus and farrowing rate, were compared between the two groups. Season was classified into two groups: cool (n = 170) and hot (n = 254), and insemination technique was classified into two groups: conventional AI (n = 171) and intra-uterine insemination (IUI) with a reduced number of spermatozoa (n = 253). On average, regular return-to-oestrus (3.3 vs. 5.6%, P > 0.05) and farrowing rates (92.8 vs. 88.1%, P > 0.05) did not differ between CONTROL and FIXED-TIME groups. However, the total born and born alive piglets per litter in the FIXED-TIME were lower than in the CONTROL group (12.0 vs. 12.8 piglets/litter; P = 0.030 and 11.3 vs. 12.2 piglets/litter, P = 0.007). Interestingly, the number of total born piglets in the FIXED-TIME group was lower than in the CONTROL group only in the sows inseminated in the hot season (11.7 ± 0.32 and 12.9 ± 0.31, respectively, P = 0.005). Piglet birth weight, variation of piglet birth weight within litter, number of piglets at weaning and body weight of piglets at weaning did not differ between groups, irrespective of the season (P > 0.05). The total number of piglets born per litter in the FIXED-TIME group was lower than that in the CONTROL group in sows inseminated via IUI (11.7 ± 0.32 and 12.9 ± 0.32, respectively, P = 0.013), but not in sows inseminated using conventional AI (12.7 ± 0.42 and 12.5 ± 0.41, respectively, P = 0.772). Single fixed-time AI could be successfully performed in sows under a tropical climate, with a promising reproductive performance. However, a decreased litter size at birth after single fixed-time AI was observed when insemination was performed in the hot season. Moreover, single fixed-time AI using IUI with a reduced number of spermatozoa also decreased litter size at birth.
我们评估了在热带气候下母猪单次定时人工授精后的繁殖性能，并研究了季节和授精技术对单次定时人工授精效果的影响。断奶后，母猪被分为 CONTROL（n=212）和 FIXED-TIME（n=212）组。CONTROL 组的母猪在发情开始后 12 和 36 小时授精，而 FIXED-TIME 组的母猪在断奶后 72 小时给予 10μg GnRH，并在 32 小时后授精。比较两组的总产仔数、活产仔数、木乃伊胎和死产仔数/窝、仔猪初生重、窝内仔猪初生重变异、定期发情和分娩率。季节分为两组：凉爽（n=170）和炎热（n=254），授精技术分为两组：常规人工授精（n=171）和经减少精子数的宫内授精（IUI）（n=253）。平均而言，CONTROL 和 FIXED-TIME 组的定期发情（3.3%比 5.6%，P>0.05）和分娩率（92.8%比 88.1%，P>0.05）没有差异。然而，FIXED-TIME 组的每窝总产仔数和活产仔数均低于 CONTROL 组（12.0 比 12.8 头/窝；P=0.030 和 11.3 比 12.2 头/窝，P=0.007）。有趣的是，FIXED-TIME 组的总产仔数仅在炎热季节的母猪中低于 CONTROL 组（11.7±0.32 和 12.9±0.31，P=0.005）。仔猪初生重、窝内仔猪初生重变异、断奶仔猪数和断奶仔猪体重在各组之间没有差异，与季节无关（P>0.05）。FIXED-TIME 组的每窝总产仔数低于 CONTROL 组，在经 IUI 授精的母猪中（11.7±0.32 和 12.9±0.32，P=0.013），但在经常规 AI 授精的母猪中没有差异（12.7±0.42 和 12.5±0.41，P=0.772）。在热带气候下，母猪单次定时 AI 可以成功进行，具有良好的繁殖性能。然而，在炎热季节进行授精时，单次定时 AI 后的出生窝仔数减少。此外，经减少精子数的单次定时 IUI 也降低了出生窝仔数。
