Seasonal variations in semen characteristics, semen cryopreservation, estrus synchronization, and successful artificial insemination in the spotted deer ( Axis axis)

Abstract

Ten adult male spotted deer were monitored over a 2-year interval to determine seasonal variations in testicular size, semen characteristics and serum testosterone concentrations, and to determine if there was an association between season and type of antler. Mean (±S.E.M.) testicular volume (118.8 ± 4.6 cm 3), serum testosterone concentration (1.2 ± 0.1 ng/mL), semen volume (4.1 ± 0.6 mL), sperm concentration (338.3 ± 24.9 × 10 6 mL −1), percentage of morphologically normal sperm (79.1 ± 2.8%), and percentage of motile sperm (66.5 ± 1.5%) were higher ( P < 0.05) in hard antler deer (peaked from March to May) than in deer with velvet antlers or in deer in which the antler has been shed. Thus, March–May was considered the physiologic breeding season for these deer; at this time, all stags had hard antlers. Furthermore, a Tris-citrate-based semen extender containing 4% glycerol and 20% egg-yolk was adequate for cryopreservation of semen. Estrus was induced with an implant containing norgestomet, timed transcervical AI was done with fresh semen, and 3 of 10 females were pregnant at 60 days, with fawns born 120 (premature), 240 and 243 days after AI. These results were considered a model for the use of assisted reproductive techniques to conserve other critically endangered deer species of India.