Checking Bulls To See If They Are Ready For The Season

In late April, prior to the start of the beef cow breeding season, Michigan State University Extension offered breeding soundness exams (BSE) for bulls. Working with Dr. Bryce Slavik of Sterner Veterinary Livestock Professionals of Westphalia, Phil Durst, Michigan State University Extension educator, set up exams on farms and at the West Branch Feeder Calf Stockyard. 

Two MSU veterinary students, Taylor Fritz of West Branch, a third-year student and Hope Catanese, a first-year student worked with Slavik and Durst at the clinic. This was a good opportunity for them to learn both the bull exam and the lab portion. 

Getting cows bred promptly impacts not only the birth date of calves and therefore, the ability to put together groups of similar size calves for sale, but the efficiency of all procedures done with those calves. Some producers aim for a 45-60 day calving window. This also concentrates the work of caring for the cows and newborn calves. More information about calving window can be found on the National Cooperative Extension website.

To get cows bred in a short time frame, bulls must be ready and able to play their role. A mature bull may be expected to breed 20-30 cows in a 30-day period. While a bull may look good, there is more to being a father than good looks! Sometimes, because of winter weather, injury, age or unknown reasons, a bull is unable to perform to the degree needed. 

During the exams, as farmers gathered at the stockyard, many shared stories of a year when either they or someone they knew found out only at calving time that the bull wasn’t much good. In some of those cases maybe they had a 40 percent or even lower calf crop. Typically, we would expect a calf crop of near 100 percent. BSE’s are performed so that farmers are not unpleasantly surprised at pregnancy check or calving time.

In those cases where many cows were unbred, the farmer must make the difficult decision about carrying those cows another year before getting a calf from them. This is expensive. That is why having bulls checked before the start of breeding season has so much value.

When a bull is checked, they get an examination that includes looking at their eyes, overall body condition and feet and legs to make sure that they do not have physical hinderances to limit their performance. A measurement of the scrotal circumference is taken to ensure they meet the minimum standard and palpation is performed to check for problems. A video explanation of BSE was prepared by Durst and Kable Thurlow.

The bull is also palpated internally for any problems, then is ejaculated so that sperm can be examined under a microscope. Sperm motility and conformation are examined. One hundred sperm cells are counted to make sure that at least 70 percent are normal. Abnormalities are often related to defects of the tail which the sperm cells use to swim.

Typically, during a day of examining bulls, 10-20% may not be currently ready, some of those will never be ready for season, while others, falling below the 70 percent minimum standard may improve. However, some bulls that we examined had only 30-45% normal sperm and are unlikely to be good enough to use. 

Breeding soundness exams, whether on farms or at a gathering place, require sturdy handling facilities that can contain different size bulls that can grow very large, some over 2000 pounds. Human safety is most important when working with all cattle, but especially with bulls, some of which have not much experience around people. On occasion, bulls have been known to ascend over gates and chutes, potentially injuring themselves and others. However, the 64 bulls brought to the late April breeding soundness exams over two days were handled safely and without incident.

The gathering of farmers is also a good time for them to compare notes on the calving season they are completing and to understand about any problems they are having. It was also a good time of fellowship over doughnuts, chili and pie.

Most of the bulls tested will be put in with cows or heifers on pasture this spring for a determined period of time. Nine months later the proof of the soundness will be on the ground as newborn calves. Michigan State University Extension helps people reach their goals. This service, a partnership with private industry, enables beef producers to reduce the risk of calf crop failure and increases the chance of success.