Welcome to the Pig Pen! October is upon us, which means many of my readers are anxiously waiting for their best sows to pass over their first heat-cycle since being bred for early January pigs. This is the time of year when I also get many calls with questions about why sows don’t settle. Is it bad semen? Is it timing? Did I use the wrong kind of AI rod? What did I do wrong?

Unfortunately, there is no silver-bullet answer to the question of seasonal infertility. It is the result of a combination of factors and a bit of a fight with Mother Nature. Our commercial farms typically over-breed during August and September, meaning they add extra breeding-age gilts to the herd which are available for breeding during those months. By breeding 10 percent more females they help offset the anticipated 10 percent drop in fertility which they normally deal with during those months and still keep producing the same number of weaned pigs weekly. They are also well-equipped for the battle with Mother Nature to keep seasonal infertility to a minimum.

The key factors contributing to seasonal infertility in sows are light and heat. Nature has provided pigs with the ability to detect the arrival of winter. Since survivability of piglets in a harsh winter climate in nature is very low, sows are naturally wired not to conceive in late summer and early fall so as to avoid farrowing in early winter. The trigger for this is light; more specifically, the days getting shorter. As the sun begins setting earlier each night, the sow is signaled to shut down reproduction for the season. This is not an issue specific to pigs. The reproductive cycle of many species is sensitive to light. Bird reproduction for example is commonly manipulated in commercial farms by exposure to light or darkness. This has been well-documented in many species.

Late-summer heat can also negatively impact fertility in sows. The primary issue with hot weather is reduced feed consumption during lactation. When sows are hot they just don’t feel like eating! Reduced feed consumption means lower lysine and energy intake, which results in sows not meeting their daily requirement while nursing. Sows become thinner and lose muscle as their bodies become stressed to meet the increasing milk demands of their growing litters. At weaning, they are poorly-equipped to restart the reproductive cycle and often will have a delayed return to estrus as their bodies start the recovery process. Those that do cycle often have shorter, less-detectable responses to boar exposure and other stimuli. This all leads to fewer sows in heat and fewer pregnancies.

Summer heat also has a negative impact on boars and their semen production. A stress event that hurts sperm cell production can take 6-8 weeks to correct (the normal time for spermatogenesis to occur). Semen doses you receive in September could still contain cells with bad morphology due to a heat-stress event that occurred in July or August! Transporting boars to shows in the middle of summer, moving from the show to a boar stud, adjusting to his new home and going through the dummy-training process are all additional stressors that can negatively impact sperm-cell production.

What can be done to combat seasonal infertility? How do we fight Mother Nature? Let’s start with the boars. In the commercial world, boar studs are well-equipped with cooling equipment to help control the climate where the boars reside. At minimum, barns are equipped with evaporative coolers and drippers, with the drippers being positioned over the rear of the boars to help cool the testicles. Some newer studs are air-conditioned, ensuring that the boars are always cool and comfortable with the temperature never reaching the point of hurting sperm production. Moving of boars from one pen to another is limited. Handling is done gently. Anything that may add to the level of stress is considered carefully before taking a step. Nutrition is an important consideration as is age of the boar and collection frequency.

Much of this goes out the window when we start talking about the showpig world! Because of the nature of the showpig business, many of the best methods to ensure quality semen production are difficult to implement, starting with the age of the boar at first collection. Often times a new boar is purchased at 6 months of age or less and collection starts immediately. Breeding seasons in the showpig world are short and the studs need to capitalize on demand while it is there in order to pay for their new boar purchases. Collection starts as quickly as possible and boars move almost immediately to twice-per-week collection. This is detrimental to long-term semen production. Stress to the boar occurs from moving to shows, home to isolation, then isolation to the main facility. This is unavoidable. Facilities in the showpig world are often times less-advanced than modern commercial boar studs, making climate control impractical or impossible. Ideal nutrition is something which showpig boar studs can implement regardless of facility design, age of the boar, or collection frequency. This is an area in which we are hoping to provide some extra assistance for our clients in the near future.

On the sow’s side of the equation, commercial farms are able to use modern technology to keep the facilities cool as well. Evaporative coolers, drippers, AC, fans, and zone cooling are all implemented to combat heat in the barns. Feed intake is minimally-impacted during lactation. Diets in summertime are changed to increase the lysine level to account for a small reduction in feed intake, ensuring daily minimum requirements are met. Lights are rigged to timers to help offset the effect of shortening days, basically trying to trick the sows and eliminate the effects of season on their estrus cycle. The most modern commercial farms have all but eliminated seasonal infertility while the average farm has at least reduced the effect.

As a small farmer, hobby breeder or showpig producer, you can also take steps to reduce seasonal infertility in your farm, even without the most modern of facilities. Water is your friend in this regard, using sprayers, drippers, or old-fashioned puddles and mudholes to keep sows cool during hot weather. Fans and air movement are also critical. Remember the important thing is to keep them eating normally, especially in the farrowing house. Increasing the lysine content in the lactation diet during hot weather is helpful. There are also nutritional supplements to help pigs during times of heat stress. TrueCOOL from True North Technologies is a supplement I strongly recommend to help with heat stress. The use of pg600 at weaning can help ensure that sows cycle on time and express strong estrus-response post-weaning as well as being a useful tool to jump-start the cycle of non-cycling gilts and sows. Have an honest discussion with your semen suppliers about semen-quality. Ask about their boar-housing and semen-collection, analysis and processing. Remember that they are dependent upon your success as well, and they are dealing with their own set of complex issues during peak breeding season. Set up a small workstation at your farm with a microscope and a few tools for analysis, such as a SimpleCount Sperm Kit, and take a look at the semen you receive before you breed your sows. Don’t automatically blame the boar stud when your sows don’t settle. Know what you’re putting in those sows first!

You can help yourself and the boar studs by having some patience with your breeding program. By patience, I mean that you don’t always have to use the most recent, popular, show-winning boar. You can increase the fertility in your farm by using some of the older, more proven sires in those studs that aren’t in as high demand. Once they reach maturity, those boars produce more volume and better quality semen, generally speaking. While the studs need to sell out the new boars, they also appreciate orders from some of last season’s superstars as well. You also are taking less risk by using proven sires with offspring on the ground for you to assess before making your breeding decision. How often are the hot new boars sold out for a season, then barely heard from again? They don’t all sire champions!

Finally, the type of insemination catheter (breeding rod) you use does not have any real impact on your success. We do recommend using our IU catheters when possible, just in case the sperm cell count in your semen dose isn’t as high as it should be. The IU (or PCAI) catheter can be helpful in achieving normal conception rates in the presence of fewer sperm cells. However, it is not going to help you at all if the semen-quality is poor, if the semen is old, if the sow isn’t cycling, etc. You can’t change your insemination timing, breed with a single dose, etc., because of the IU catheter. Don’t believe the hype and misinformation that has been spread regarding IU (PCAI) technology. This isn’t new. We’ve been doing this for more than 15 years.  

The month of October usually provides relief from the effects of seasonal infertility. I’ve been in many farms where gilts in the “old maid” pen which haven’t been seen in heat in August or September magically all start cycling when October arrives. Sows start coming into heat post-weaning in a much more timely manner. Gilts and open sows coming off of Matrix feeding all cycle like clockwork. The incidence of recycling sows from October breeding is minimal as semen quality starts to improve as well. Why? The effects of summer heat-stress have passed and the young boars in the studs have matured by a few more months. Mother Nature is back on our side again and the battle is finished until next August!

You’ve been nervously checking those September-bred sows only to find some of them recycling. Now all those sows which you thought were going to give you early January pigs will settle on this cycle and give you late January and early February litters instead. While you probably can’t eliminate seasonal infertility, you can at least take a few steps to improve your chances next year!

No questions to answer today! Hopefully I addressed them all in today’s blog post. Have a great week everyone! – Darin.

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