A common and frustrating problem veterinarians find when doing breeding soundness examinations (sometimes referred to as BSE) is seminal vesiculitis — an inflammation of the vesicular glands. These glands are located in the pelvis, and they secrete fluid that helps transport sperm when a bull breeds a cow. When the glands are inflamed, pus and white blood cells are found in the semen, which can lower fertility.

Most bulls with seminal vesiculitis don’t appear sick. Occasionally, a bull may be reluctant to mount or act painful when palpated. In most cases, the only way the problem is detected is during a breeding soundness exam, either by rectal palpation of the glands or when the semen sample is examined under the microscope and white blood cells are seen. Sometimes the semen looks thickened, brownish or blood-tinged.
Effect on fertility

Seminal vesiculitis can interfere with semen quality. If the sperm cells themselves are abnormal along with the presence of pus or white blood cells, it means the bull has problems that include the testicles or epididymis. While some bulls with vesiculitis are still able to settle cows, the odds of subfertility are much higher.

The causes and likely outcomes of seminal vesiculitis are different between young, yearling bulls and mature bulls. Many young bulls will spontaneously recover during several weeks or months; but in older bulls, the disease is far less likely to resolve on its own. Management appears to play a role. Young bulls housed in confinement and fed high-energy rations are more likely to develop vesiculitis than bulls raised on pasture. This ties in with research showing a connection between high-energy diets, rumen acidosis and certain bacteria that are commonly isolated from infected glands.

Treatment options

Diagnosis is based on a combination of rectal palpation and semen evaluation. Normal vesicular glands feel lobulated, like a bunch of grapes. When inflamed, they often feel smooth, enlarged or firm. Ultrasound can also be used to confirm changes in the glands. It is important to note pus in the semen can also come from other parts of the reproductive tract. A thorough exam is necessary to rule out other sources, such as the prepuce or epididymis.

Treatment of seminal vesiculitis is challenging. Antibiotics are commonly used, but results are inconsistent. Because of this, prognosis depends heavily on the age and value of the bull. Young bulls often improve with or without treatment, though it is impossible to predict which ones will recover. Older bulls with chronic disease seldom recover and are usually culled.

When bulls are diagnosed with vesiculitis, they should be reevaluated within a few weeks. If semen quality does not improve, their usefulness for the upcoming breeding season is questionable. Since the factors that lead to seminal vesiculitis are not always clear, prevention can be difficult. Still, certain practices may lower the risk, including avoiding high-energy diets that push rapid weight gain in young bulls and providing a clean, dry environment with adequate space for exercise.

Seminal vesiculitis is a relatively common finding at the time of a breeding soundness exam and can be a frustrating condition for both veterinarians and cattle producers. While young bulls frequently improve, older bulls are less likely to recover. Because treatment options are limited, the best strategy is good bull management and timely breeding soundness exams, so problems are detected early. 

Editor’s note: Robert L. Larson is a professor of production medicine and executive director of Veterinary Medicine Continuing Education at Kansas State University in Manhattan, Kan.