Detomidine as an inducer of ejaculation in a stallion with penile melanotic melanoma: case report

Resumo

Equine semen collection is a fundamental component of breeding programs and is typically performed using artificial vaginas. However, conditions such as neurological and penile injuries, psychogenic ejaculatory dysfunction, and reduced libido may make conventional semen collection unfeasible. In such situations, pharmacologically induced ejaculation represents a valuable alternative, although the effectiveness of available agents remains variable. Detomidine hydrochloride, an α2-adrenergic receptor agonist widely used in horses for sedation, analgesia, and muscle relaxation, may represent a promising option for ejaculation induction. This study reports a case involving a 20-year-old Mangalarga Marchador stallion diagnosed with advanced melanotic melanoma in which conventional semen collection was not possible. An ejaculation induction protocol consisting of intravenous administration of 0.033 mg/kg of 1% detomidine hydrochloride at five-day intervals for two months was applied. Ejaculation occurred in 72.73% of attempts. Semen evaluation revealed low ejaculate volume but a high sperm concentration, allowing its use for cryopreservation. Despite the limited literature regarding the use of detomidine hydrochloride for ejaculation induction in stallions, this case demonstrates that the drug may represent a feasible and effective alternative for semen collection when traditional methods are not viable.