Abstract

Semen collection in lemur species is notoriously challenging as the ejaculate forms a coagulum. Following natural mating, this coagulum forms a copulatory plug, designed to give a genetic advantage to the breeding male by preventing copulation with other males. However, during semen collection using electroejaculation the semen may coagulate during or after emission. The coagulum can become lodged in the urethra and lead to chronic urine retention. A new technique has shown promise for preventing urethral plug formation following electroejaculation in lemurs. As semen collection has not been conducted routinely, sperm parameters are not well-known. Other factors that may influence sperm quality and production, such as seasonality, are also relatively unknown.

Four ring-tail lemur (Lemur catta) males of breeding age were collected according to an IACUC approved protocol in late January 2007, at the end of the established breeding season. Animals were anesthetized and collected using a previously described electroejaculation protocol. Urethral catheters were passed on all males and the urethra and bladder flushed with ascorbic acid and saline until a steady stream of urine was easily manually expressed. No urethral plugs were formed. All animals were monitored during recovery until normal urination was observed. All animals urinated within hours post-collection. Semen was evaluated for motility, concentration and progressive motility. Testes measurements were also recorded. Samples were cryopreserved; however, post-thaw yield was disappointingly low indicating that further investigation into semen preservation and seasonal effects on sperm quality are warranted. The absence of urethral plugs following semen collection is quite encouraging and is further evidence that semen collection in lemurs can develop into a conservation tool for these unique animals. The low post-thaw yield may be related to seasonal differences in sperm viability and further investigations are warranted.