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While breeding season may be a ways off, making sure our bulls are cared for throughout the winter — and ready to go when it’s time to turn out —is critical. A sound and fertile bull can mean the difference between success or failure of next year’s calf crop. While AI is a valuable tool, across the U.S. about 87% of operations still utilize bulls in some capacity.
Winter care for bulls can be broken down into two categories: body condition and fertility. Let’s look at body condition first. Bull condition going into breeding season is a major factor in breeding success. A bull-to-cow ratio in the 1:20 to 1:30 range is often a reasonable starting point, but pasture size, terrain, multiple breeding groups, bull age, and social dominance can shift that number. Libido and dominance matter, too—one study noted individual bulls servicing anywhere from 4 to 8 o females during the breeding season.
The energy required to meet the demands of breeding is substantial, and bulls can be expected to lose 100 to 250 pounds during the course of the breeding season—sometimes more in tough conditions or very active breeding situations. Getting bulls back into condition for next year is one of the primary winter goals. Typically, we want bulls back to about a Body Condition Score of 5V2 to 6 before turnout next year.
To do this, take a body condition score now if you haven’t already and develop a plan for feeding. Remember that young animals may not yet be fully grown, so they’ll need additional energy and protein to continue growth and build condition. Forthis reason, depending on the number of bulls in a herd, separating mature and younger animals into separate groups can make meeting feed requirements for each group easier.
Meeting mineral requirements is also important. Research has shown that selenium and zinc are key in supporting reproductive function and sperm production, and other trace minerals like copper and manganese also play roles in overall structural soundness. The key is a balanced mineral program.
The second factor to consider with bulls during the winter is fertility. Major impacts on fertility in the winter months are cold stress and frostbite on the scrotum. Even minor injury can affect fertility, but we really want to protect against major damage that can eventually result in blistering and scabbing. At that point, sperm production can be significantly impacted. Sperm production takes roughly two months, so damage can have longer-term effects. Watch for swelling, discoloration, scabs, or roughened skin when you’re checking bulls.
Even in a winter likethis—more open, dry, and fairly mild overall—cold injury can still happen. All it takes is a sharp, windy cold snap along with mud or wet bedding. If bulls can’t get out of the wind or stay dry, frostbite risk goes up fast.
If you suspect cold injury, make a plan early. Consider evaluating inj ured bulls and scheduling a breeding soundness exam about 45 to 60 days after an injury has occurred. Even if animals appear sound, don’t forget to schedule a regular BSE 30 to 60 days before turnout so you have time to make replacement decisions if needed.
It’s better to know early that a bull won’t be ready than scrambling last minute.
To keep cold damage to a minimum, do your best to protect animals from wind and cold. Provide plenty of space for animals to find shelter and use windbreaks to cut down on wind-chill impacts. A layer of bedding helps insulate animals from the cold ground and—just as importantly—helps keep them dry, reducing the risk of cold injury.
While bulls may not be our first focus this time of year, don’t forget to give their care some thought. Evaluate body condition and have a plan to get bulls back to a BCS 5V2 to 6 before breeding season. Maintain a balanced mineral program, keep an eye on feet and mobility, and provide wind protection and bedding during cold stretches. A little attention now helps safeguard fertility and prevent unwanted surprises later on.
— Ben Beckman is a beef systems Extension Educator serving northeast Nebraska. He is based out of the Cedar County Extension office in Harrington. You can reach him by phone: (402) 254-6821 or email: [email protected] mailto:[email protected]
