Bull Breeding Soundness Evaluation (BSE)

October, 2010
Courtney Davis - Extension Agent I, Dairy/Water Quality, Okeechobee County Extension


Once a year all bulls on your operations should have a Bull Breeding Soundness Evaluation. A BSE should be conducted by a veterinarian at least 30 to 60 days before breeding season should start. This will allow time for retesting bulls or time to purchase (a) new bull(s).

A BSE should be consists of four basic steps:

  1. Visual assessment of feet, legs, eyes, teeth and external genitalia.
  2. Palpation of accessory sex glands
  3. Measurement of scrotum and palpation of testis and epididymis
  4. Collection and microscopic evaluation of semen sample

The physical exam is important, some of the main reasons for a physical exam are as follows:
  • Bulls need sound feet and legs to be very mobile to breed as many cows/heifers as possible.
  • Eyes should be examined. Bull locate estrous females primarily though visual observation rather than olfactory cues (smell).
  • Internal and external genitalia are important because if a bull has an injury or infection he will not breed as well or not all.

Semen evaluation consists of a microscopic examination of the sperm cells for concentration, motility (percent alive) and morphology (percent normal). During semen collection the veterinarian should expose the penis for a visual examination to determine if there are any abnormalities. Studies have shown that bulls that are tested and have satisfactory semen have an increase in pregnancy rate.

Bulls should have a strong libido (sexual desire) to properly perform. Even if a bull has the ability to breed, he can still be infertile if he lacks the desire to mate. Studies have shown that high-serving capacity (high libido) bulls have increased pregnancy rate as well as earlier conception rates. This can result in over $50 more gross income in cows.

There should be anywhere from a 1:25 to 1:60 bull to cow ratio. A ratio of 1:25 would insure that your bull would be able to service the cows properly. This is the normal male-to-female ratio. A young bull (two-year old) should be able to successfully mate with up 60 cows/heifers in a short period of time.

The BSE cannot predict conception rates. Some sound =bulls can have very low conception rates, and some unsatisfactory bulls can have acceptable conception rates. The BSE is used to identify and eliminate unsound breeders rather than to make a prognosis on fertility. This must be understood by sellers and buyers.

Remember that one bull in five will not be a satisfactory potential breeder. A complete BSE is important in all situations, but is even more critical in single-bull cow herds. This examination should be conducted every year at least 30 to 60 days before breeding season to allow adequate time to find a replacement bull if needed.

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