Seasonal infertility continues to be a widespread problem for sow herds across the US. And if you don’t have a problem with seasonal infertility, it may mean you are not recognizing it, reported Daniel Gascho, DVM, with the Four Star Veterinary Service office in Mexico, Indiana.
Gascho offers several suggestions for recognizing and dealing with seasonal drops in fertility that occur in late summer and early fall but may not be noticed until winter.
“The signs can range from the obvious of just a lot of sows and gilts are not pregnant and I don’t know why,” he said. “But for people focused on breeding, they may notice delayed return to heat after weaning. You may notice, when they do cycle again, that it’s at an unusual time and not on a normal 21-day cycle. Or you may notice she was pregnant and then she lost it.”
Causes for seasonal issues
Many factors are involved in seasonal infertility. Top of the list is hot weather when sows don’t like to eat or breed, according to Gascho.
Another big factor is poor nutrition caused by mycotoxins or poor corn quality. “We sometimes jokingly refer to it as ‘combine-itis’ because people working in the fields this time of year are busy, and general husbandry drops a bit,” he explained. “They are not paying as close attention to the things that play a role in infertility.”
Other stressors can cause infertility problems like moving sows too quickly after breeding, crowding or fighting in gestation pens, and not pushing feed intake while sows are nursing piglets.
“But you could have a perfect farm, and you’re still going to see a drop in fertility this time of year,” he added. “That’s the part we don’t fully understand. A lot of people suspect it has to do with natural hereditary instinct of swine where wild pigs quit breeding in September so they don’t have litters during the winter.
“Our commercial animals aren’t affected by temperatures, but some scientists hypothesize it has to do with photosensitivity — the length of the day.”
Strategies to manage infertility
Regardless of the cause, producers can follow management strategies to minimize the seasonal infertility issues.
Because heat is the leading cause of infertility, Gascho recommends using cool cells, misters and ventilation rates to keep ambient temperatures low and sows comfortable. This equipment also must be checked regularly to make sure it is working.
“When sows are too hot, they don’t feel like eating, which makes them not maintain their weight, which makes them not breed well,” he said.
Reduce feed issues by paying attention to quality, especially in the fall when last year’s crop has been stretched to cover until the new crop is harvested. That’s when Gascho sees a spike in feed-related issues like mycotoxins, mold contamination, odor, lower quality and poor nutrition.
Keep sows healthy by providing adequate feed. “Make sure you’re pushing feed intake during stressful times in their lives when they are nursing piglets or you are trying to get them to ovulate,” he added.
To help manage infertility problems, Gascho suggested, “Heat checking twice a day to find [females] that are not bred. Sort them out and get them rebred. This may require ultrasound to check for pregnancy at 4 weeks if that’s appropriate for your farm.”
Focus on animal husbandry
In addition, Gascho recommends closely following good husbandry practices to reduce infertility issues.
“We just have to focus extra hard and make sure we do all of the things that we can control exactly right so we don’t have that on top of this seasonal or inherent thing that always happens,” he said. “Don’t get discouraged because everybody fights this.
“The best way to manage it is to find [unbred females] right away and do something about it so they don’t disappear into your herd and 3 months later, half of them aren’t pregnant.”