Comparison of two pharmacological protocols for inducing ex copula ejaculation in donkeys

Abstract

This study aimed to compare the efficacy of two pharmacological protocols for inducing ex copula ejaculation in donkeys. Seven healthy jacks (male donkeys) aged 4 to 20 years (median 8 years) and weighing 136.2±4.17 kg (mean±SE) were enrolled. Using a crossover design, each jack was subjected in a random order to two treatment protocols (IX and IDO) with an interval of 7 days between the two protocols. Each jack was orally administered 3 mg/kg imipramine hydrochloride followed 2 hours later by intravenous (IV) administration of 1.1 mg/kg xylazine hydrochloride (IX protocol) or 0.02 mg/kg detomidine hydrochloride and 20 IU total dose oxytocin (IDO protocol). The jacks were monitored for behavioral changes and ejaculation up to 3 hours from the beginning of each protocol. A total of 22 ex copula ejaculation replicates were attempted. Both protocols resulted in deep sedation and partial to complete penile protrusion in all jacks. There was no difference in the efficacy with the IX protocol inducing ejaculation in 1 of the 11 replicates and the IDO protocol inducing ejaculation in none of the 11 replicates. The results suggest that neither of the two tested pharmacological protocols were effective in inducing ex copula ejaculation in donkeys.

Keywords: Detomidine; Donkey; Imipramine; Semen collection; Xylazine.