A breeding soundness exam (BSE) is an examination of a bull’s ability to produce viable sperm. A BSE is administered by a veterinarian and should be conducted at least 30 days prior to the breeding season.

A typical BSE has three components:
1) scrotal circumference,
2) physical evaluation, and
3) semen evaluation.

Scrotal circumference is the measurement of the distance around the widest part of the scrotum of a bull. Yearling bulls must have a scrotal circumference that exceeds 30 cm to pass a BSE. Data indicate that semen output and serving capacity are highly correlated with scrotal circumference. In other words, bulls with a larger scrotal circumference will produce more semen and can service more cows than bulls with a smaller scrotal circumference.

The second component of the BSE is the physical exam. The physical exam consists of a visual appraisal of the animal for its general health and well-being and its structural correctness. Lame bulls service fewer cows. The physical exam also consists of a rectal palpation of the bull's sex organs and extension of the penis to ensure that are no abnormalities.

The final component of the BSE is evaluation of the semen. Sperm cells are evaluated for the morphology (i.e., how they look) and their motility. Bulls that ejaculate abnormal sperm cells are graded lower and have a reduced ability to impregnate cows.

Most technicians assign a score to bulls subjected to a BSE. Only use bulls that receive a high score on the exam. Bulls that are marginal or substandard should be avoided. The BSE is a highly accurate tool for identifying infertile bulls.