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 cm³), serum testosterone concentration (1.2 ± 0.1 ng/mL), semen volume (4.1 ± 0.6 mL), sperm concentration (338.3 ± 24.9 × 10⁶ 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.