Seasonal variations in scrotal circumference, sperm quality, and sexual ability in rams.

Seasonal variations in scrotal circumference, spermatozoal motility, morphologically normal spermatozoa, libido, and serving capacity were studied in Suffolk, Lincoln, Columbia, and Polypay rams (5 of each breed). There were marked seasonal variations in the scrotal circumference, morphologically normal spermatozoa, libido, and serving capacity for each of the breed types. Mean scrotal circumference was highest from August through October and lowest in February. Spermatozoa that were morphologically normal were highest in proportion in September (82.3%) and lowest in proportion in February (57.8%). Libido and serving capacity scores were highest from September through November and lowest in March.