Postmortem assessment of sperm characteristics of the red deer during the breeding season.

This study examined the effect of male age, time lapse between death of individual and collection of its sperm, breeding season (1993, 1995, or 1996), and testicle sampled (left or right) on the cell quality of spermatozoa obtained postmortem from the epididymis of red deer stags (Cervus elaphus hispanicus). A total of 142 sperm samples obtained from 71 free-ranging individuals shot during the breeding season were used to investigate these effects. The spermatozoa were obtained from the cauda epididymis of stags. Immediately after collection, an assessment was made of the proportion of motile spermatozoa (PM), normal morphology (PN), intact acrosomes (PIA), and the osmotic resistance degree of the plasmatic spermatozoa membrane as determined by the cell endosmosis test (E+). Gamete quality was influenced by both the age of the individuals and the lapse between death and collection of sperm (p < 0.001), whereas the year of collection and testicle sampled did not affect sperm quality. Sperm samples were classified in three groups: excellent, acceptable, or unacceptable, depending on the values achieved in the PM, PN, E+, and PIA variables. Acceptable samples had to achieve the following score: PM > 40%, PN > 40%, E+ > 40%, and PIA > 60%. Within this group, samples with a PM > 60% were classified as excellent. The percentage of samples classified as viable (strictly acceptable plus excellent) achieved 59.8% (85 out of 142). These results indicate that it is possible to obtain a remarkable percentage of viable sperm after the death of the deer. This finding might also be useful to obtain embryos of threatened species of wild ungulates.