11/4/2021 Fall/Winter Bull Management #444

Winter is a time when many beef producers are thinking about the condition of their bred cows, but Lisa Pederson, NDSU Extension beef quality assurance specialist, encourages producers to not forget their bulls. Pederson joins Sound Ag Advice to discuss how to ensure the health of bulls during cold weather.

Speaker 1: Kelli Anderson, NDSU Ag Communication Specialist
Speaker 2: Lisa Pederson, NDSU Extension Beef Quality Assurance Specialist

Kelli: This is Sound Ag Advice, a weekly feature presented by NDSU Extension. I'm Kelli Anderson and I'm joined this week by Lisa Pederson, NDSU Extension Beef Quality Assurance specialist. Now for many North Dakota beef producers, they're probably gearing up for calving season. And they're thinking about keeping their cows in good shape. But we're here to talk about bulls today, specifically, about not forgetting the bulls over the winter time. So Lisa, first let's talk about how cold weather might affect both semen quality and body condition score, specifically. If a bulls in thin shape, how might that affect his semen quality over the winter?

Lisa: Yes, Kelli. And you're right, we do tend to forget about the bulls over the wintertime. We throw them in a corral and thrown some hay and we don't always tend to think about how winter management of bulls impacts their fertility long term. And so you asked about body condition score we know that bulls that are in a body condition score three to four and even a lower five, at breeding soundness exam time, bulls have a lower fertility rate than bulls that are in a body condition score of upper five, six or seven. And so, we really need to think about the nutritional level of our bulls, especially our younger bulls, they're still growing, they're losing some teeth. And so just throwing them some poor-quality hay may not be meeting their nutritional needs.

Kelli: So now let's talk about cold weather injury. So, when the weather's really cold, should we be thinking about frostbite or other injuries to bulls?

Lisa: Yes, so one of the things we saw last winter in particular was frostbite injuries on the scrotums or the scrollable area visible, and some work done up in Canada shows that bulls that have frostbite injury that is larger than a penny, one or more of those, have significantly lower semen quality at breeding soundness time. And it doesn't matter when those breeding soundness exams are taken, after they've had that injury, their breeding quality, their semen quality goes down time that we know at least three months. And so one way that we can mitigate that is to bed bulls, give them some straw, hay to lay in something like that. And then give them some windbreak to get away from that wind. And again, body condition is going to help that as well. It'll provide some insulation to injury to the testes, if those scrotums do happen to get frostbitten.

Kelli: Lisa, any final thoughts on management of bulls over the winter?

Lisa: Kelli, I think we need to remember that our bulls should be in a body condition score four to seven, ideally a five to seven over the winter and moving into breeding season. And then when they are turned out with cows that will make a big difference in their fertility. Secondly, I'd encourage producers to maintain young, recently purchased bulls on a similar plane of nutrition as when they were purchased. And I know that I guess the urge is to go home and dump them out. But really give them some high-quality nutrition, and then step them down in that nutritional plane over a longer period of time. Check out the body condition score of your herd sires, not just your cows. I think it's a good time to take an overall look at the nutritional status and the body condition of your herd and then develop a ration to meet that, again provide windbreak and bed those bulls. And remember within about a month of turnout, when you're going to turn those bulls out to breed to get breeding soundness exams. That will be very important to the long-term fertility of your herds.

Kelli, now is also a good time to evaluate your bull battery. If there's some bulls in your herd that you would like to cull or move on to market, now's a good time to do that. And so, look at their feet and legs for soundness look at their penis and their scrotums for injury, see if they're still sound. Look at their dispositions, if they haven't been wanting to stay home and go visit the neighborhood, maybe now's a good time to get rid of them as well. That way we don't have to feed them over the winter and that'll save you on some hay and some feed as well.

Kelli: Great advice from Lisa Pederson, our NDSU Extension Beef Quality Assurance specialist. We thank her for her time. This has been Sound Ag Advice, a weekly feature presented by NDSU Extension.

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