Winter Bull Management Is Important For Breeding

Bulls are like athletes. When game day rolls around, they need to be ready to perform. Winter management is a big part of that.

Heather Smith Thomas

November 1, 2011

9 Min Read
Winter Bull Management Is Important For Breeding

Bulls are expensive; they’re also half the genetics of your calf crop. That means they need as much care through winter as your cowherd.

“Taking care of bulls is like having a maintenance program on your vehicles,” says Larry Melhoff, 5L Red Angus, Sheridan, MT. “If you don’t take care of a young bull, it’s like running a vehicle 100,000 miles without an oil change.”

Operations that don’t manage bulls properly are often those with more open cows, says Ram Kasimanickam, a DVM in Washington State University’s Department of Veterinary Clinical Sciences. It pays to fine-tune bull management as much as possible in order to give them optimum conditions for health and fertility, he says. That means nutrition, health care and an off-season management program.

Nutrition is important

Kasimanickam reports studies have shown that a body condition score (BCS) 5 is adequate for a breeding bull, but yearlings need special attention because they’re still growing. While feed supplies and sources vary from ranch to ranch, the main thing is to make sure young bulls have adequate nutrition to keep growing and stay in adequate body condition. Depending on the severity of the winter, they may need more energy to keep warm, too.

Bulls should be neither underfed nor overfed; they need optimum body condition before the next breeding season to have enough stamina to cover their cows. If bulls come out of the herd a little thin, some producers tend to over-feed them.

“Fat layers around the scrotum insulate the testes and can interfere with proper thermoregulation,” Kasimanickam says. “The sperm parameters and sperm production will be adversely affected in overfed bulls. This is why lean-to-moderate body condition is better than over-fat bulls.”

It’s also important for health reasons, he adds, as overfeeding with grain can lead to acidosis and liver abscesses, or foot problems.

Make sure feeds don’t contain endophyte-infected fescue or other plant toxins that act as vaso-constrictors, which interfere with circulation to the extremities.

Bulls also need proper levels of trace minerals and vitamins for good sperm production. “Vitamins A and E, selenium, copper, zinc and manganese serve as cell protectors and prevent damage to sperm from stress. Stress-damaged sperm will result in reduced fertility; even if fertilization occurs, the resultant embryo will fail to develop,” Kasimanickam says.

Learning your soil profiles will provide clues to deficient minerals. The vitamin-mineral program should be part of year-round management, and not just seasonal. Bulls should be on the same mineral and vitamin supplement program as the cows.

Weather protection

Testicles are at risk in cold weather if bulls can’t get out of the wind. “Scrotal frostbite adhesions will hinder the bull’s ability to raise or lower the testicles for proper thermoregulation. This can adversely affect sperm production and parameters,” Kasimanickam explains.

There’s a good chance of recovery with mild frostbite, but severe frostbite can leave a bull infertile. “Prevention is the best course; producers should ensure that bulls have windbreaks and bedding.”

Ken Dunn, an Angus breeder near Tetonia, ID, has windbreaks in every pen and also creates mounds of piled straw in his bullpens.

“If you keep adding more straw to the pile, the straw mixed with manure ferments and generates heat. Our bulls climb on those piles to sleep; it’s surprisingly warm,” Dunn says.

Conversely, if bulls lie on unbedded, frozen ground, it robs body heat and increases frostbite risk. Having mounds to bed on is healthier in wet conditions also as bulls don’t have to lie in mud.

Joe Van Newkirk, a purebred Hereford breeder near Oshkosh, NE, utilizes trees for windbreaks. “We get severe weather, with wind chills of -40°F. If it’s really bad, we take a big bale or two of straw out there, so the bulls can bed in that instead of on frozen ground or snow,” he says.

Health program

While most producers have good vaccination and parasite control programs for the cows, the bulls are sometimes ignored, Kasimanickam says.

Craig Bieber raises Red Angus seedstock near Leola, SD, and says his bulls and cows are on the same health program. In addition, the bulls are dewormed with a purge dewormer when brought in after breeding season.

“We wait to do lice treatment closer to the first of the year and may do it again about the first of March. It seems like we need to do this more often for bulls than cows. We monitor them to see if they need another treatment before spring,” Bieber says.

Dunn’s bulls are also on the same vaccination program as his cows. “Everything gets an 8-way twice/year and a modified live 4-way shot before breeding season. We deworm everything in the fall. We treat cows for flukes when we vaccinate for scours, and treat bulls for flukes in early spring when they get their spring shots. We also do a pour-on in the spring to help control flies,” he says.

He pours his cattle in the fall for internal and external parasites. This usually works for lice through the whole winter, but he occasionally re-treats bulls for lice before spring.

“We use squirt guns and apply a topical product while we’re feeding. After we’ve put the hay out, while the bulls are standing there eating, we walk up behind them and squirt each one. That’s an easy method, since our bulls are gentle,” Dunn explains.

Social order

Minimizing the risk of injuries to bulls from sparring means social order must be managed. So, when bulls are removed from the cows and put into their fall/winter pastures, Bieber makes sure the groups are eased back together and allowed to get their differences settled.

“If they’re too confined, they fight more. You not only can have injuries, but it’s tough on the facilities,” he says. It’s always good for bulls to have lots of space.
When Van Newkirk removes bulls from his cow groups in July, he puts yearling bulls and older bulls in separate pastures.

“When I turn those bulls together, I shut them away from water for the first 24 hours. If they’re riding and fighting in hot weather, they become extremely hot; if they go take a big drink of water, they may water founder. We let them get their differences settled and cooled down before we let them into water,” he says. The bulls soon establish a pecking order, and there’s not much fighting after that.

“They establish this within the first day or two. We try to throw them all together on the same day, or as quickly as possible,” Van Newkirk says. It’s easier on the bulls, he adds, as they’ll all fight one another and no single bull gets picked on. “If you keep adding bulls to a group, the newcomers are outnumbered and ganged up on; some may be run to exhaustion.

“We have a smaller pasture where we temporarily keep yearlings and new bulls, and put them with the older bulls later. Usually the old bulls tend to leave the young ones alone,” he says.

If an older bull becomes a problem, Van Newkirk gets rid of him. “We rarely have problems with older bulls that constantly fight. If two of them can’t quite settle it, they eventually get tired of wrestling and tend to go off to their own sides of the pasture. This is the advantage of a large pasture. This usually works until you have to move the bulls, and then we bring one of those rivals in at a time, never together,” he says.

Dunn says it pays to separate young bulls from the older ones through their first winter. “Then, they don’t have to fight for feed or their place in the hierarchy. This also allows you to feed them a different ration – one that the older bulls may not need,” he says. A mature bull should regain enough body condition on good hay alone.


Van Newkirk winters his herd bulls in a quarter-section of pasture, with trees for windbreaks. They have room for exercise and have fewer injuries or problems than if kept in a corral.

“We put 18-20 herd bulls in a pasture together, and they’re bunk-fed a mix of ground alfalfa, ground grass hay and a little corn silage. We spread the bunks out over a large area to lessen competition,” he says.

Giving bulls plenty of room is important, he adds. “It gives them room to get away from one another and room to exercise. We have fewer foot and leg problems,” he says. Plus, it’s a lot easier on the corrals.

Van Newkirk’s bull pastures are also situated away from other pastures. “It’s important not to have bulls across the fence from other cattle,” he says.
Bieber also winters bulls in a pasture some distance from the cows. He says there are many kinds of facilities that work for bulls.

“Some bullpens are very stout, and I’m sure they work well, but I’m not sure they’re cost-effective. We’ve found that hot wire is very effective for bulls. Once they learn and respect it, they don’t try to go through or over a fence. Bulls seem more aware of hot wire than cows or calves,” Bieber says.

Dunn winters a large number of bulls, including 175 weaned bull calves. The weaned calves are in 30- to 40-acre pastures of about 75 animals each, with straw piles in each corner for the calves to lie on.

Two other groups of bulls, 4-5 animals in each, are kept together. But the operation’s top 6-8 herd bulls are housed in individual pens that are 14 ft. wide and 100 ft. long.

“Using individual pens allows us to keep these bulls away from each other and prevent fighting. We turn them out on grass as soon as we can,” Dunn says.

Developing bull calves

If bulls are purchased as yearlings, their development phase is very important. Seedstock producers should condition young bulls to be physically fit with hard muscle, not fat, Melhoff says.

“They should be developed in big pens with adequate exercise, so they don’t have to go directly from soft condition to breeding cows in big pastures,” he adds.

Melhoff strives to minimize his bulls’ nutritional transition from off-season to breeding season. “It makes it easier for the bull and he won’t fall apart by the time he’s removed from the cows,” he says.

“Fifteen years ago, we didn’t have enough large pens for our bull development, so I made a ¼-mile-long lot at the edge of a field, and put 50 young bulls there. It was a sacrifice of a hay meadow for a bull run but we needed the room. It had water at one end and the feed bunk at the other, with ¼ mile in between. It worked well so we added another run. We now handle about 400 bulls in several quarter-mile runs, with feed and water at opposite ends,” Melhoff says.

“The extra room and exercise sorts out any that have structure issues or foot problems, and we take them out of the program before they go to our customers. Bulls developed as athletes go out and do their job and bounce right back. The worst thing you can do is put them on good feed with no exercise.” he says, adding: “The commercial producer’s bull management is made easier by how well we as seedstock producers develop the bulls.

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