Will Your Bulls Be Ready Come Turnout Time?
When it comes to winter bull care, proper management can avoid heartache.
We all know bulls have a very important job on our operations. We are starting to see some light at the end of the winter tunnel, but many states had some extreme cold this winter. What does that mean for bull fertility? What can you do to make sure your bulls are ready when breeding season starts? In an episode of Angus at Work, our team sat down with veterianarian Jeff Erquiaga to discuss considerations to keep in mind during bull-sale season and beyond.
Cold weather can be hard on livestock in a number of ways. One of particular importance when considering a bull acquisition is the effect cold weather could have on bull fertility.
Frostbite occurs when skin freezes during exposure to frigid temperatures. Symptoms in humans can include pain, numbness, swelling, blisters and skin discoloration. Since cattle can’t tell us when something is wrong, being vigilant during times of below-freezing temperatures is imperative.
“I think the cold temperatures aren’t really a terrible problem if you’ve got adequate bedding and decent protection. But, when you add the wind that we had with the extreme cold, the scrotum tends to hang down there kind of in a bad spot for Mother Nature,” noted Erquiaga. “When you get that much wind, it tends to cause frostbite. When that happens, you’ve got a little bit of a mess on your hands.”
Frostbite can vary in severity, from just a small portion of the scrotum to a fairly significant injury. Three consequences can cause trouble with sperm production: heat, inflammation and infection, says Erquiaga. In frostbite cases all three can be present, which can mean intermittent infertility or — in some severe cases — permanent infertility, said Erquiaga.
Another potential concern of scrotal injury is the development of scrotal adhesions. These adhesions, much like scar tissue, affect the ability of a bull to move the testicles up and down and thus regulate heat. This can pose an issue during warmer summer months, as the bull can't regulate heat and, consequently, sperm fertility can drop or cease altogether.
Erquiaga expressed concern regarding incidence of damage to the epididymis of the testicle.
“There's a lot of little tubules that make up the epididymis, and sometimes those will actually get damaged enough that they freeze together and no longer is there a patent way for the sperm to even come out of there,” he said. “So, if you’ve got any of those particular problems occurring, your fertility is not going to be very good.”
There is some good news: If severe weather occurs in the earlier portion of the winter, even bulls injured by severe temperatures might have the ability to recover before turnout.
Spermatogenesis takes approximately 62 days, meaning a sperm cell takes two months to go from ground zero to a viable sperm. From the time producers see the scrotum beginning to heal up, they would be wise to start counting those 62 days.
“If you find a bull that’s not a satisfactory breeder right now, I would certainly give that bull an opportunity and some time if you’ve got that. If you’re in a position where you're going to start breeding before too long, then obviously that’s not something that you can do,” said Erquiaga. “I think a lot of these guys need to evaluate their bulls visually. Look them over and see how many bulls you’ve got that look like you’ve got some frost damage. I think maybe you better plan on replacing at least a percentage of those bulls.”
Erquiaga is not suggesting producers replace all breeding bulls after a severe winter weather event. Still, he estimates somewhere between 30% and 60% of bulls tested with a breeding soundness exam (often referred to as a BSE) will be infertile. As sales approach and prices potentially rise, producers will likely need to make plans to replace more bulls than they typically would.
So what can producers do to mitigate the risks of buying a bull with frost injury? According to Erquiaga, a breeding soundness exam is a great start. Bulls should be checked for adhesions and that both testicles are present. If the answer to those two questions is favorable, bulls should then have a semen sample collected to ensure the morphology and motility of the sperm are normal and that the sample contains at least 70% normal sperm cells.
In addition to fertility-related conversations, there are a number of other physical fitness aspects that come into play for breeding cattle. Bulls must be able to do their job and move throughout a pasture with ease. If a potential bull is a poor mover, has structural issues or swollen joints that could affect his performance, it’s time to remove that bull from contention as a breeding piece.
Though quality, tested bulls may not be readily available to producers within a certain area, there is nothing barring producers from purchasing bulls elsewhere as long as they’re prepared to help those bulls acclimate to new conditions.
Producers shouldn’t be afraid to ask their seedstock supplier what practices are in place to protect potential herd sires from winter weather. Erquiaga noted that most seedstock suppliers do a great job of ensuring that adequate bedding is down and bulls aren’t exposed to freezing temperatures without safeguards. Occasionally, buyers might see a bull with mild freeze injury, but employing management practices to protect fertility is standard practice for many seedstock producers.
“Bulls can stand a lot of cold if they just don't have wind blowing up their backside,” Erquiaga said. “If you’ve got windbreaks, tree rows or even someplace to get them in out of the extreme weather, I think it’s not a bad idea because you’ve got quite a bit of money invested in your bulls.”
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Another incidence Erquiaga cautions producers against is taking a bull that’s been on a high-concentrate diet during the development phase and then kicking him out on a lower-quality feed. Bulls put in that predicament tend to lose a lot of weight, and that weight loss can be a limiting factor when it comes to that bull’s fertility. Erquiaga suggested backing bulls down gradually over time to try to get their digestive tract conditioned back to a more forage-based diet and reduce stress from a sudden change.
The information above is summarized from the March 1, 2023, episode of Angus at Work. To access the full episode, including further information regarding what to keep in mind when purchasing bulls and what to implement when it comes to winter bull care, check out Angus at Work on Apple Podcasts or use the QR code to save time.
