Proposed Technique for the Prevention of Urethral Plug Formation after Electroejaculation in Lemurs
Abstract
Substantial coagulum is produced in many primate species following electroejaculation, posing a significant obstacle to semen collection. Prolonged retention of a urethral plug consisting of coagulated vesicular secretions leads to abnormal urinary retention and eventual death. Thus, in species where urethral plugs form, any artificial semen collection can pose a serious health risk. Deposition of a vaginal or copulatory plug has been documented in some species of lemur1,3,4 and may indicate a greater likelihood of urethral plug formation in lemurs following electroejaculation. Urinary retention secondary to urethral plug formation following electroejaculation in lemurs has been reported.2 Therefore, development of a safe method for electroejaculation in lemurs is critical to the establishment of assisted reproductive techniques in these endangered species.
Semen was collected from apparently healthy ring-tailed lemurs (Lemur catta, n=4) and ruffed lemurs (Varecia sp., n=2) of breeding age (>4 y) using electrostimulation following an IACUC-approved protocol at the Gladys Porter Zoo. Each animal was collected twice 3–4 weeks apart. After fasting for 8–12 hours, the animals were manually restrained for isoflurane administration via facemask. Once anesthetized, a 2.5×15 cm rectal probe was inserted. Following successful electroejaculation and digital rectal prostatic massage of 10–20 sec, a 3.5-Fr. urethral catheter was passed and 0.5 ml of 25% ascorbic acid was infused while the catheter was removed. Lactated Ringer’s solution was administered subcutaneously to each animal following semen collection. Two ring-tailed lemurs were used in a crossover design, in which each animal served as its own control, collected with and without the urethral catheter and ascorbic acid treatment. When not treated with ascorbic acid, the urethra was simply expressed, and the animal was allowed to recover from anesthesia. Semen was successfully collected from all males and was very viscous and granular, solidifying within 1 minute of exposure to room air. Both animals produced urethral plugs without treatment, but not after urethral infusion of ascorbic acid. All lemurs receiving the urethral infusion post-ejaculation urinated within 2 hours after collection.
In these two species of lemurs, thorough post-collection urethral and prostatic massage combined with the passage of a urethral catheter for administration of ascorbic acid appears to decrease the incidence of urethral plug formation in lemurs after electroejaculation. Further studies are needed to fully assess the efficacy of this protocol, but urethral catheterization with ascorbic acid administration appears to ameliorate the risk previously associated with electroejaculation in these species.
Literature Cited
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