Effect of semen collection method on sperm motility of gray wolves (Canis lupus) and domestic dogs (C. l. familiaris)

Abstract

Genetic management of Mexican gray wolves includes semen banking, but due to the small number of animals in the population and handling restrictions, improvements in semen collection and cryopreservation rely on results from studies of domestic dogs. Semen collection from wolves requires anesthesia and electroejaculation, which introduce potentially important variables into species comparisons, as dog semen is typically collected manually from conscious animals. To investigate possible effects of collection method on semen quality, we compared semen collection by the traditional manual method and by electroejaculation (EE) in a group of dogs (n = 5) to collection by EE only in wolves (n = 7). Samples were divided into two aliquots: neat or diluted in Tris/egg yolk extender, with motility evaluated at intervals up to 24 h. There were no differences (P > 0.10) in sperm motility in either neat or extended samples at 24 h from EE dogs and wolves, although motility of the wolf neat samples declined more rapidly (P < 0.05). However, there were differences (P < 0.01) between EE and manually collected dog semen in motility at 24 h, in both the neat and extended samples. Therefore, general motility patterns of dog and wolf semen collected by EE were similar, especially when diluted with a Tris/egg yolk extender, but sperm collected from dogs by EE did not maintain motility as long as manually collected samples, perhaps related to the longer exposure of EE samples to more prostate fluid.