Preparing Bulls for the Breeding Season

To maximize herd bull performance this breeding season, SDSU Extension encourages cattle producers to evaluate their bulls’ nutritional status and overall well being.

“Winter is a stressful time for cattle in the Northern Plains,” said Ken Olson, Professor & SDSU Extension Beef Specialist. “Producers often pay less attention to the bull battery through the winter – turning most of their focus to the cow herd. However, bulls that have been carried through the winter have been impacted with the stress of winter weather as well.”

Olson along with his colleague, Adele Harty, SDSU Extension Cow/Calf Field Specialist, list some bull pre-breeding season management considerations below.

“Managing the situation in early spring will be tremendously important to avoiding unpleasant surprises next fall when the cows are pregnancy checked,” Harty said.

Nutritional status: Mature bulls typically do well through the winter on a maintenance diet.

“In fact, the concern in mild winters is that bulls may be overfed – which can result in them being too fat and negatively impacting their reproductive capacity,” Harty said.

Winter 2016-2017 was not mild. “This winter required a total energy expenditure by cattle that was greater than normal maintenance requirements,” Olson explained.

He added that there is a good likelihood that nutrient intake was reduced in bulls who were turned out to graze through the winter because deep snow limited forage access.

“Either situation alone can lead to negative nutritional status, but the combination guarantees it,” he said.

Body condition scoring (BCS): BCS can be performed on bulls in the same manner as cows.

On the scale of 1 to 9. “Bulls should be in moderate condition at this time of year,” Harty said.

She explained that bulls should be at or near a BCS score of 5. “As the breeding season approaches, bulls in moderate BCS should maintain or slightly increase condition so they are slightly above moderate at the beginning of breeding,” Harty said.

If bulls are thinner than a BCS of 5 at this time, Harty encourages cattle producers to consider improving their feed intake today in order to gradually improve their BCS before breeding season.

Alternatively, bulls that have been overfed through the winter and have excess BCS – 7 or greater – can be given a lower quality diet to gradually decrease BCS to a moderate level by initiation of breeding.

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Reproductive Soundness: After a harsh winter, ensuring bulls are fertile and reproductively sound is the largest concern.

“The opportunity for frostbitten testicles has been high this winter,” Olson said. “This can cause reduced sperm production that may be temporary, but is likely to be permanent.”

Conducting breeding soundness exams on all bulls is recommended in all years, but it will be particularly critical this year because of the increased probability of cold stress injuries.

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Exam Timing: Timing of the breeding soundness exam can play a role in the value of the results. It is a balancing act that needs to be based on the health and body condition of the bulls, opportunities to find replacements after the exam for bulls that fail and probably other issues that are unique to each situation.

“Conducting the exam early can be useful to determine which bulls fail and need to be replaced while there are still plenty of bull sales to find replacements,” Olson said.

On the other hand, Olson added that bulls still have the opportunity to become injured or contract diseases which could impact fertility later in the spring – which could mean they become infertile after the exam.

Bulls that fail the exam early may recover, Harty added.

“Follow-up testing may be needed if the initial breeding soundness exams are done early,” she said.

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–SDSU Extension