Merck Manual

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Professional Version

Breeding Soundness Examination of Rams


Sylvia J. Bedford-Guaus

, DVM, PhD, DACT, Peekskill-Cortlandt Veterinary Hospital, Westchester Veterinary Associates

Reviewed/Revised Apr 2014 | Modified Oct 2022

In rams, the breeding soundness examination (BSE) is performed much as for bulls, using an electroejaculator with a smaller (ram) probe. Body score is classified as 1–2, questionable (underconditioned); 3–4, satisfactory; and 5, questionable (overconditioned). Any major abnormalities of the external genitalia or lumps or irregularities of the testes or epididymides render the ram unsatisfactory. Epididymal masses are commonly found to be sperm granulomas caused by infection with Brucella ovis, which is a major cause of reproductive loss in sheep. B ovis may also be associated with testicular atrophy. Scrotal circumference should be ≥28 cm for rams 8–14 mo old (>36 cm is exceptional) and ≥32 cm for rams >14 mo old (>40 cm is exceptional). Scrotal circumference lower than satisfactory is questionable. Motility of individual spermatozoa is evaluated as for bulls, with >70% progressive motility being exceptional, >30% satisfactory, 10%–30% questionable, and 0% unsatisfactory. The percentage of morphologically normal sperm should be >50%; between 30% and 50% is questionable, and < 30% unsatisfactory; >80% normal sperm is exceptional. Presence of >5 WBCs per high power field is questionable (WBCs are correlated with B ovis infection). An ELISA test for B ovis should be done on range rams and rams >9 mo old. A positive test renders the ram unsatisfactory. Suspect tests should be repeated. (Also see Ram Reproductive Management Ram Reproductive Management To achieve maximal fertility, rams should be physically examined for reproductive fitness before breeding to detect any abnormalities that may affect reproductive ability. The scrotum and its... read more .)

Any ram with one unsatisfactory rating in any parameter is classified “unsatisfactory”; a ram with a questionable rating in any parameter is “questionable.” For a ram to be classified exceptional, he must have exceptional ratings in scrotal circumference, sperm motility, and sperm morphology. All other rams are considered “satisfactory.”

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