Management of breeding stallions is crucial to equine reproduction. The longevity of the breeding career is the ultimate objective, whether the stallion is used for natural cover or for semen collection and artificial insemination. Stud farm veterinarians should be aware of the techniques used to evaluate testicular function and the diagnostic approach to testicular disorders in cases of emergency. This paper presents the clinical methods used to evaluate testicular health, including palpation, ultrasonography, biopsy, and fine-needle aspiration. The discussion of testicular disorders is broken down into four categories: congenital disorders (cryptorchidism, monorchidism, and testicular hypoplasia), differential diagnosis of scrotal enlargement, differential diagnosis of causes of progressive testicular enlargement, and differential diagnosis of testicular asymmetry or reduction in size with an emphasis on testicular degeneration. The sudden increase in testicular size is often accompanied by severe clinical signs and is a major cause for referral of stallion for surgery. Testicular disorders are illustrated with clinical cases seen by the authors.

Objective was to determine whether addition of coenzyme Q10 - ubiquinol to glycerol extender improved cryopreserved ram sperm quality. Semen was collected (electroejaculation) from mature Suffolk rams (n = 6) 6 times during the breeding season. Pooled semen from each session was processed and cryopreserved in extenders with 150 µmol/liter of ubiquinol (treated) and without (control). Thawed cryopreserved semen was evaluated using computer-assisted sperm analysis for motility and kinetic parameters. Sperm viability was determined via plasma membrane integrity. After thawing, measurements were obtained at 10, 20, 60, and 120 minutes. In treated samples, there were increases in progressive motility (p < 0.0001), curvilinear velocity (p = 0.002), straight line velocity (p = 0.003) and time average velocity (p = 0.001), and sperm tended (p = 0.07) to have more viability. Furthermore, there were time-related decreases in all variables in treated control and samples. Ubiquinol improved cryopreserved ram sperm quality.