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据明尼苏达州圣彼得市猪兽医中心临床兽医博士（DVM）Paul Yeske所说，夏季母猪繁殖性能下降，今年亦如是。
标题：How to minimize summer’s impact on sow fertility 如何最大限度地减少夏季对母猪繁殖的影响
他说：“一般到了每年的第29到40周，我们会观察到生殖性能的下降。对于更靠近中西部地区的我们而言，5月下旬和6月初的炎暑会让这种下降比一般来得更快一些。”
“We typically see reproductive performance drop off as we get to week 29 through 40,” he said. “With hot weather in late May and early June, we may see it a little quicker than normal for us in the upper Midwest.”
为了将季节性不孕的影响降到最低，Yeske建议养殖者采取措施，保持11月和12月的生产业绩平稳。
To minimize the impact of seasonal infertility, Yeske recommends producers take steps to keep November and December farrowing numbers up.
环境影响
Environmental impact
季节性不孕的一个主要原因是整体环境温度，可通过多种方式调整。Yeske说：“缓解措施包括增加通风率，使用蒸发降温，如降温单元、滴水降温器或喷雾器，或组合使用，保持母猪尽可能舒适。”
One main cause of seasonal infertility is overall environmental temperature, which can be handled several ways.“Mitigation steps include increasing ventilation rates and using evaporative cooling like cool cells, drip coolers or misters or a combination to keep sows as comfortable as possible,” Yeske said.
他解释说：“通常这一时期，母猪21日返情率上升，母猪受孕差。”
“Typically, we see in this period more 21-day returns to heat, so sows are not conceiving as well,” he explained.
“过去这些数字更糟糕。如今在2-5%之间，不是特别大，但每年此时都会发生。”
“In the past, those numbers would be more exaggerated. Today, they are in the range of 2% to 5% and not a huge number, but it does show up this time of year.”
日照长度变化
Day length changes
季节性不孕的另一个原因是日照长度的变化。Yeske说：“日照缩短，母猪不想怀孕并在隆冬时节产仔。”
The other cause of seasonal infertility is the change in day length.“As day length shortens, the sows don’t want to be pregnant and farrow in the middle of the winter,” Yeske said.
“出现更多不规律的返情。母猪受孕后，无法维持妊娠或吸收胚胎。”
“We see more irregular recycles. The sows were pregnant, and they either lose the pregnancy or reabsorb the litters.
他补充说：“我们必须找到这些动物并决定是否再次配种，把它们留在群内，还是淘汰掉，鉴于它们的生产性能不尽如人意。我们不希望它们留在场内占用空间和时间。”
“We want to be sure to identify these animals and decide if we are either going to get them rebred and back into the system, or cull them because performance is low,” he added. “We don’t want them sitting around taking up space and time.”
Yeske建议尽早查情，因为有更多21天返情的母猪。在50-60天左右认真进行第二次孕检，找出早期胚胎流失的动物。
Yeske recommends heat checking early, because there are more 21-day recycles, and being diligent with second pregnancy checks around 50 to 60 days to pick up early pregnancy losses.
他解释说：“就以往而言，接近11月份，我们会发现这些母猪本该产仔，但一些母猪却无仔猪。”
“Historically, we would see some sows not-in-pig as we get to November when those animals should be farrowing,” he explained.
“若我们现在可以发现，那我们便不会让未孕的它们占据空间直至11或12月。”
“If we can get them identified now, then we don’t have them tie up space until November or December and not have litters.”
一些猪场使用照明来应对日照长度的变化。计时器每天设置亮灯16小时，模拟一年中最长的日照。
Some farms use lighting to help counter the changes in length of daylight. Timers keep lights on up to 16 hours a day in a bid to mimic the longest day of the year.
这种照明的影响仍未可知，但Yeske说，许多猪场使用这种方法，也不难办。
The impact of this lighting is hard to say for sure, but Yeske said many farms use this approach and it isn’t hard to do.
如可能，提高配种目标
Increase breeding target if possible
减少季节性不孕的另一个选择是如有空间，给更多母猪配种。
Another option for minimizing seasonal infertility is to breed more animals if you have the room to do so.
Yeske解释说：“猪场使用历史信息，根据以往的经验，额外配种2-3%的母猪来弥补。”
“Farms will use their historical information to compensate by breeding, in general, 2% to 3% more animals, depending on what they’ve seen in the past,” Yeske explained.
过去需要借助公猪时，季节性不孕是一个更大的难题。
Seasonal infertility used to be a much larger issue when boar services were required.
“公猪受热应激影响，精液质量下降，”他说。“随着人工授精的普及，这个问题已大大缓解。”
“Boars would get heat stressed, and semen quality would go down,” he said. “With nearly everything switching over to artificial insemination, we’ve been able to mitigate that issue.
“但季节性不孕症仍每年出现，”他补充道：“虽然损失不大，但总有一些……因此，我们越早发现问题，尽快重新配种，让动物进入生产周期，以维持高效生产。”
“But seasonal infertility still shows up every year,” he added. “While the losses aren’t big, there are always some…so the quicker we get them identified, the quicker we can get animals bred back and into the system and be as efficient as possible.”
原文链接：https://www.thepigsite.com/articles/how-to-minimize-summers-impact-on-sow-fertility
