A breeding soundness examination is an evaluation of the potential ability of a male to impregnate a defined number of females within a specified breeding period. It represents an assessment at a particular time and does not guarantee future fertility. The primary goals of the examination are to identify males with inferior reproductive potential, remove them from the breeding population, and improve overall reproductive efficiency and economic returns. This is particularly important because a substantial proportion of rams presented for breeding are of unsatisfactory breeding quality. A secondary objective is identification of superior males capable of impregnating more females than the average male.
The breeding soundness examination consists of a physical examination with emphasis on reproductive fitness followed by semen evaluation. Libido and social behavior are not routinely tested during the examination but rather rely on producer observation and history. Unlike routine clinical examinations, temperature, pulse, and respiration are not prioritized. Instead, attention is directed toward feet, eyes, and body condition. Lameness prevents males from locating and mounting females, and visual impairment interferes with detection of estrous females. Inadequate or excessive body condition decreases breeding activity and stamina.
Evaluation of the reproductive tract includes palpation of the scrotum, testes, and epididymides. Testes should be of similar size, consistency, and resilience. Any asymmetry, nodules, firmness, or irregularities should be considered clinically significant. Scrotal circumference should be measured because it correlates with sperm production, reproductive efficiency, and age at puberty in female offspring (see ). Scrotal circumference is also moderately heritable. Interpretation of scrotal circumference must account for the male’s age and seasonal influences.
The prepuce should be palpated externally and the penis evaluated, when possible, most commonly during semen collection.
Courtesy of Dr. Clare Scully.
Semen collection is an integral component of the breeding soundness examination. Spermatogenesis requires approximately 49 days, followed by an additional 10–14 days of epididymal maturation, meaning that sperm collected on the day of examination began development approximately 2 months earlier.
Semen is commonly collected using electroejaculation, particularly in males that are untrained or unable to mount (see ). Prior to collection, the rectum should be cleared of fecal material and water-soluble lubricant introduced to protect the rectal mucosa. The probe must be thoroughly lubricated before insertion. Electrical stimulation is initiated at the lowest setting for several seconds and gradually increased until ejaculation occurs. The ejaculate is collected in a clean insulated container. Restraint is often required, and vocalization can occur. Electroejaculation is recognized as stressful but is not considered painful when performed correctly.
Courtesy of Dr. Clare Scully.
After collection, semen is evaluated for concentration, motility, and morphology. Progressive motility is assessed by diluting semen with warm saline, placing a drop on a prewarmed microscope slide, applying a coverslip, and examining under low magnification. All equipment must be maintained near body temperature because cold shock rapidly decreases motility.
Morphological evaluation is performed using a prewarmed eosin-nigrosin stain under oil immersion microscopy. One hundred sperm cells are evaluated and classified as normal or abnormal with defects categorized as primary (involving the head) or secondary (involving the midpiece or tail). The presence of nonsperm cells, such as inflammatory cells, should also be recorded because they might indicate underlying reproductive tract disease. Any unsatisfactory parameter renders the male unsuitable for breeding, whereas questionable findings warrant correction of reversible factors and repeat evaluation.
Semen Classification in Rams
All breeding soundness examination parameters were developed in rams during the normal breeding season (see the table ).
Male Breeding Soundness Evaluation
Classification | Unsatisfactory | Questionable | Satisfactory | Exceptional |
|---|---|---|---|---|
Body condition score (1–5) | Subjective | 1–2 or 5 (under- or overconditioned) | 3–4 | N/A |
Scrotal circumference (8–14 mo) | Subjective | < 30 cm | 30–36 cm | > 36 cm |
Scrotal circumference (> 14 mo) | Subjective | < 32 cm | 32–40 cm | > 40 cm |
Progressive sperm motility (individual) | < 10% | 10–30% | 31–70% | > 70% |
Normal sperm morphologya | < 30% | 30–50% | 51–80% | > 80% |
Modified from Bulgin MS. Ram breeding soundness examination and SFT form. In: Proceedings of the Annual Meeting of the Society for Theriogenology; 1992:210-215. | ||||
a Morphology should be identified using phase contrast on formalin-fixed wet mount under oil immersion or using prewarmed eosin-nigrosin stain under light microscopy under oil immersion. The presence of more than five WBCs per high-powered field should result in deeming in the semen "questionable." Serological testing for Brucella ovis should be considered a routine part of a breeding soundness examination, and animals with positive test results should be culled. Rams suspected of B ovis infections should be retested in 30–60 days and considered questionable until those results are obtained. | ||||
Semen is classified according to the following rating system:
Any unsatisfactory reading of motility and/or morphology should be collected a second time.
Any unsatisfactory rating is considered Unsatisfactory.
Any questionable rating is considered Questionable.
Exceptional requires exceptional ratings in all categories (except BCS).
All other animals are Satisfactory.
Semen ratings are interpreted as follows:
Unsatisfactory: Animals should be culled or treated and retested.
Questionable: Animals might be able to breed a limited number of animals under limited conditions or be treated to change a questionable rating to a satisfactory rating and retested in 30–60 days. It might be suggested that offspring not be kept for breeding purposes.
Satisfactory: Animals might be expected to impregnate at least 50 ewes under normal conditions in a 60-day breeding season.
Exceptional: Animals might be expected to impregnate at least 100 ewes under normal conditions in a 60-day breeding season. This rating should generally not be used to classify rams for sale but rather to choose rams for special breeding programs, such as artificial insemination.
For More Information
Tibary A, Boukhliq R, El Allali K. Ram and buck breeding soundness examination. Revue Marocaine des Sciences Agronomiques et Vétérinaires. 2018;6(2):241-255.
Shipley CF. In: Chenoweth PJ, Lorton SP, eds. Applied andrology: ram and buck. Manual of Animal Andrology. CAB International; 2022:108-119.
