Novo protocolo utilizando ocitocina para induzir a ejaculação em garanhão penectomizado / New protocol using oxytocin to induce ejaculation in penectomized stallion

ABSTRACT

Background: Several reproductive diseases can prevent ejaculation by the traditional method of collection. Neoplasias as squamous cell carcinoma is the most common tumor of the external genitalia of horses and its lesions usually prevent copulation. The pharmacological induction of ejaculation is an important alternative technique to obtain and preserve the genetic material of stallions incapable of ejaculating by traditional methods of semen collection. However, the protocols currently used have shown questionable results and new protocols are needed in order to increase the success rates. The aim of this study is to report the success of a new protocol in inducing ejaculation when oral imipramine and intravenous oxytocin and detomidine were administrated in a Crioulo stallion.Case A 9-year-old Crioulo stallion was admitted at the Veterinary Hospital of the São Paulo State University, FMVZUNESP, Botucatu, Brazil, with a history of a mass located on the glans and body of the penis. The histopathological exam confirmed the diagnostic of Squamous cell carcinoma and penectomy was performed. After 10 days of surgery the stallion was submitted to 5 different protocols with 3 days interval between the follow protocols Imipramine+Xylazine; Imipramine+ Xylazine+Oxytocin; Imipramine+Detomidine and Imipramine+Detomidine+Oxytocin.Discussion: The traditional protocol of pharmacologically-induced ejaculation with imipramine hydrochloride (3 mg/kg/v.o) and xylazine hydrochloride (0.66 mg/kg/iv) was not successful even when oxytocin (20 UI/iv) was added to this protocol. Administration of imipramine hydrochloride (3 mg/kg/v.o) two hours prior to administration of detomidine hydrochloride (0.02 mg/kg/i.v) also did not result in ejaculation. However, administration of imipramine hydrochloride (3 mg/kg/v.o) 2 h prior to administration of detomidine hydrochloride (0.02 mg/kg/i.v) associated with oxytocin (20 U.I/i.v) resulted in ejaculation.[...]