Abstract
Thirty-one ejaculates from 18 captive-living cheetahs (Acinonyx jubatus) maintained at three zoological institutions in Japan were collected by rectal probe electrostimulation, and evaluated. Thirteen of the males had no reproductive history. Semen characteristics (mean±SEM) recorded were as follows: semen volume, 0.91±0.11ml; semen pH, 8.1±0.1; total sperm count per ejaculate, 32.6±5.4 million; sperm viability, 84.9±1.9%; sperm motility index, 53.7±3.8; sperm abnormality, 66.1±3.4%; and percentage of sperm with a normal acrosome, 68.5±5.1%. These values were approximately in the range of the results reported in other cheetahs. These parameters, except for the percentage of sperm with a normal acrosome, were not significantly different between the fertile and subfertile males. The acrosomal integrity in the subfertile males (59.8%) was significantly lower than that in fertile ones (86.9%), but even the values in the former were not necessarily fatally low. This result indicates that their poor semen quality may not inhibit reproductive efficiency in captive male cheetahs in Japan.
