Spermatozoan numbers and testicular characteristics of male white-tailed deer fawns during the mating season

Testicular spermatozoan numbers, testes weight, testes length, body weight, and kidney fat index (KFI) were obtained for male white-tailed deer Odocoileus virginianus (Zimmerman, 1780) fawns during the mating season at the Savannah River Site (SRS) in South Carolina. Mean values for testicular spermatozoa, testes weight, and testes length increased significantly over the study period (late October - late December) whereas body weight and KFI did not change with time. Testicular spermatozoa were found in 28% of all fawns examined and the proportion of sexually mature fawns increased greatly over the course of the study and was highest during December. These findings suggest that male fawns breed later than adults at a time that coincides with the mean conception date in doe fawns. Testes weight, testes length, body weight, and KFI were significantly greater in fawns with testicular spermatozoa compared to those without testicular spermatozoa. We suggest that testes weight is closely associated with the presence of testicular spermatozoa in fawns from SRS.