BSE

Bull Breeding Soundness Exams

There are many bull-related factors that can reduce fertility and ultimately result in fewer calves to sell at weaning. Performing a breeding soundness exam (BSE) on your bull before turnout can prevent major headaches and save money in the long run. A good BSE helps avoid the unpleasant surprise at pregnancy check that your bull didn’t get cows bred.

A BSE evaluates several factors to ensure a bull is capable of successfully breeding females.

1) Overall Health

A bull’s overall health can greatly impact reproductive performance. If an animal has a systemic illness, both semen quality and the bull’s desire to breed—known as libido—can be reduced.

2) Body Condition

Body Condition Scoring (BCS) helps ensure bulls have adequate energy reserves but are not overly fat. In cattle, BCS is measured on a 1–9 scale, with 5–6 being ideal for breeding bulls.

During breeding season, bulls often lose weight because they spend more time traveling and breeding than eating. Entering the breeding season in good condition helps ensure they have enough energy to maintain performance throughout the season. However, excessive fat—especially in the scrotum—can negatively affect fertility.

3) Feet and Legs

Sound feet and legs are critical for breeding success. Bulls may need to travel long distances and mount multiple cows during the breeding season. Lameness can quickly limit a bull’s ability to service cows.

A BSE is also a good opportunity to trim hooves if needed. Certain breeds are predisposed to structural issues like screw claw, which can often be identified during the exam.

4) Reproductive Tract Evaluation

During the exam, the scrotal circumference is measured and the testicles are palpated. Scrotal size is related to fertility and can help estimate how many cows a bull may be able to service.

A rectal exam is also performed so the veterinarian can evaluate the accessory sex glands for abnormalities such as infection.

The penis and sheath are closely examined as well. An electroejaculator is used to stimulate ejaculation so a semen sample can be collected. This process also allows the penis to extend from the sheath so its structure can be evaluated.

Certain problems can interfere with breeding ability, including:

• Persistent frenulum in young bulls

• Penile injuries

• Hair rings

• Penile warts

Many of these issues can be identified—and sometimes corrected—during a breeding soundness exam.

5) Semen Evaluation

Once the physical exam is complete, a semen sample is evaluated under a microscope. Two main factors are assessed: motility and morphology.

Motility refers to the sperm’s ability to move forward. Under the microscope, healthy sperm typically create a swirling motion on the slide. Dead or sluggish sperm that only wiggle in place are a negative indicator.

Morphology refers to the shape and structure of sperm. The head, midpiece, and tail are examined for defects. While a small percentage of abnormal sperm is normal, most sperm must appear normal for the sample to be considered satisfactory.

Occasionally, white or red blood cells may also be seen in a semen sample, which can indicate infection or injury.

In 2025, Apogee Animal Health expanded our semen evaluation capabilities by adding a phase-contrast microscope, allowing us to identify abnormalities that are difficult to see with standard microscopes. We can also attach a camera to the microscope so producers can see exactly what we are seeing in the semen sample.

6) Breeding Classification

After the exam, bulls are placed into one of three categories:

Satisfactory – the bull meets all standards and is ready to breed cows.

Deferred – the bull does not meet standards today but may improve. A recheck is recommended in about four weeks. This often occurs with young or immature bulls.

Unsatisfactory (Failed) – the bull is unlikely to become a satisfactory breeder and should be replaced.

It is important to remember that a BSE represents a snapshot in time. Even bulls that pass a BSE can experience fertility problems later due to illness, injury, or heat stress. Some issues are temporary, but severe injuries—such as frostbite of the scrotum or major penile injuries—can permanently affect fertility.

7) Trichomoniasis Testing

Trichomoniasis (trich) is a venereal disease of cattle that occasionally occurs in Kansas. Bulls show no symptoms, but they can spread the infection to cows during breeding.

Infected cows often experience early pregnancy loss, which results in open or short-bred cows at pregnancy check.

There is no treatment for infected bulls, and positive animals must be sold for slaughter. Many producers only discover a problem when they find far more open cows than expected.

Non-virgin bulls or bulls of unknown breeding history are at risk of carrying trich. Bulls can even become infected by breeding a neighbor’s cow through the fence. Testing bulls before the breeding season is an important way to protect your herd.

Final Thoughts

A breeding soundness exam is essentially an insurance policy for your breeding season. It helps ensure your bull is capable of getting cows bred before he is turned out.

BSEs should be performed close to the start of breeding season, but early enough that there is time to find a replacement bull if needed.

If you have questions or would like to schedule breeding soundness exams, contact Apogee Animal Health today.