Winter weather management plans ensure bull fertility success

It is critical for producers to manage bulls during the winter, considering they contribute one-half of the genetics to a cow herd.

Producers must consider several factors, including protection from winter weather and exercise to ensure semen quality.

Harsh winter weather can impact a bull’s ability to breed successfully, so providing appropriate shelter, bedding and feed is critical to its success.

Producers know winter can be challenging for cow herds, but Karla Wilke, Nebraska Extension specialist, reminds them to keep their bulls in mind during the winter and create a solid management plan. 

“Bulls are one of the bigger investments in the cow herd, and 90 percent of cows are still impregnated through natural service with a bull rather than with artificial insemination,” Wilke states. “So, they also require year-round maintenance.”  

Incorporating a bull management plan during winter months can enhance bull performance during the upcoming breeding season.

Frostbite

Winter weather can create a variety of scenarios in which bulls can become injured. Providing windbreaks and bedding can help protect bulls from the frozen ground and wind chill.

“Lack of protection from the frozen ground or continual snow presence could lead to blisters or scabs on the testis from frostbite, which could permanently lower sperm-production capabilities,” Wilke says. “When a bull’s testicles are injured from frostbite, it could make it harder for them to pass their breeding soundness exams.” 

She further notes evidence of frostbite to the scrotum is usually apparent a few days after freezing in the form of noticeable inflammation and swelling.

“When looking for evidence of frostbite, damaged tissue will appear as a scab, discoloration or sloughing of the lower portion of the scrotum,” Wilke explains.

Frostbite can be prevented by providing heavy bedding, a shelter or windbreak for bulls to escape the weather. 

Bedding is essential to help mitigate the cold by providing insulation from the frozen ground or snow and keeping cattle clean. 

In addition, providing protection from wind and cold temperatures can help bulls maintain their body condition, reducing additional supplementation support to help maintain their body temperature.

She adds, “Since sperm is produced over 60 days before breeding a cow, cold stress in late winter may negatively affect sperm production and fertility, resulting in low fertility early in the spring breeding season.”

What to watch for

South Dakota State University (SDSU) experts found severe and persistent cold weather can stress a bull’s system, so they will need more dietary energy for body maintenance.

SDSU’s research notes anytime there is a period of extreme temperature change, bulls can have a period of subfertility, especially if they lack good nutrition or protection.

Also, fast-changing weather can lead to illnesses affecting fertility. 

For instance, a bull with a fever or pneumonia may not be able to recover sufficiently in time to breed, and when the bull’s body temperature elevates, it interferes with spermatogenesis.

SDSU Professor and Extension Veterinarian Dr. Russ Daly concludes, “It is important for bulls to go into winter months with a strong body condition score around a six and to schedule bulls for breeding soundness exams at least 60 days prior to the start of breeding season.”

He notes increased lameness caused by harsh weather, including sprains, strains and dislocations, can affect an animal later on if they do not heal in a timely fashion or if the injury remains chronic. 

Movement on and through ice, snow and mud can put a strain on the bull’s feet and legs, affecting its ability to travel on pasture.

“In a similar manner, bulls standing in persistent mud can be prone to foot rot. If these cases go untreated or evade detection, the infection can extend into one of the coffin joints and wall off into an abscess which creates long-term lameness,” he mentions.

Exercise

Many experts maintain bulls need adequate exercise in the winter to maintain their stamina during the spring breeding season. Therefore, producers should spread out water, feed and minerals to require bulls to walk around.

Patrick Davis, University of Missouri Extension regional livestock field specialist, says exercise before the breeding season is important to make sure bulls are physically ready for breeding.

“Since many bulls service females in pastures, they are accustomed to walking long distances. The breeding process demands physical activity,” he says. “Therefore, producers should make exercise a part of winter management.”

Keeping a bull in proper condition requires producers to focus on body condition, reduce stress and allow for adequate exercise.

Melissa Anderson is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.