- 11 -
Breeding Soundness Evaluation of IBEP Bulls
Wayne L. Singleton, Professor Emeritus, Department of Animal Sciences, and
Larry Horstman, D.V.M., Department of Veterinary Clinical Sciences
Purdue University
Upon completion of the performance test, the top indexing of their breed are examined
for breeding soundness (BSE).
Classification of a bull for breeding soundness begins with a physical examination.
Observation is made for any condition which might handicap a bull’s ability to locate cows in
heat and serve them. If a bull has severely impaired vision, motion injuries, or is unsound, his
breeding ability will be adversely affected and will be ineligible for IBEP Auctions.
Palpation of the scrotum, testicles and seminal vesicles indicates size, shape and
consistency. Normal testicles should be nearly equal in size, quite firm and free of adhesions,
abscesses and inflamation. Scrotal circumference (SC) is also measured because SC, testes size,
sperm production and pubertal age of half sisters and daughters are correlated. To be eligible for
IBEP Auctions, Simmental bulls must have at least 33.0 cm adjusted SC. Angus, Gelbvieh, Red
Angus, and Red Poll bulls must have at least 32.0 cm adjusted 365-day SC. All other breeds
must have at least 30.0 cm adjusted SC.
The penis is closely observed during semen collection for abnormalities such as tumors,
adhesions, persistent penile frenulum or “tagged” penis, injuries, or other conditions which make
the bull incapable of breeding. Bulls with reproductive abnormalities which are heritable, or are
likely to recur if corrected, are ineligible for IBEP Auctions.
An electroejaculator is used to collect semen from bulls in the test station because it is the
most rapid procedure and bulls need not be trained or halter broken. Semen is evaluated for
motility and sperm number immediately after collection. A stained slide is made for evaluating
sperm morphology at a later date.
No single test will give an absolutely accurate estimate of bull fertility. In fact, by using
all known tests one cannot predict that a bull will settle 90, 65 or 40% of the females exposed to
him. It is possible, however, to separate obviously sterile bulls from fertile bulls and to identify
those of low or unsatisfactory fertility. Using the above criteria, bulls are scored as either
satisfactory or unsatisfactory. Only bulls receiving a satisfactory BSE are sale qualified and
receive the official IBEP brand. This scoring system does not take into account libido level or
breeding ability. Also, remember that it is possible for various injuries, adhesions, changes in
sperm quality and other problems to occur after bulls leave the test station. Therefore, be sure to
observe your bull(s) closely during the breeding season.
For a detailed description of the Breeding Soundness Exam, please visit the IBEP web
site at
.
