SPERMATOGENESIS IN THE TAIGA-MOOSE OF NORTH CENTRL ONTARIO A PILOT STUDY

Abstract

Testes of 128 moose between the ages of 6 months and 15 years were collected in Jun (1), September (4), October (108), November (11) and December (4) of 1977 and 1978. Weights of testes and epididymides and the pattern of spermiogenic activity (SA) were investigated. A wide individual variation of testicular weight and SA-pattern occurred within each age class. Some yearlings may have achieved puberty at the end of September, but most exhibited this stage in October. With increasing age (2 1/2 to 4 1/2 yr.) the peak of SA shifted gradually from mid-October to mid-September. In 5 1/2 yr. bulls the peak could be in early September. The most stabilized trend of SA is in the class of 6 1/2 - 9 1/2 yr., with  a maximum reached speculatively around the end of August or by the beginning of September. The longest period of SA was found in the 4 1/2 - 5 1/2 yr. class. In primes (6 1/2 - 9 1/2 yr.) and older seniors (greater than 10 yr.) the SA declined sharply by the end of November and terminated in December. The relatively high frequency of partially or completely emptied tubules of epididymal ductuli and vas deferens was surprising. We concluded that bulls of this population matured at 5 1/2 yr., and the 6 1/2 - 9 1/2 yr. group was fully prime. The results are compared with data from Minnesota and the USSR.