Reproduction in the Male Ferret: Gonadal Activity During the Annual Cycle; Recrudescence and Maturation

Abstract

Ten mature male ferrets and one castrate male ferret were housed outdoors and monthly blood samples and testis measurements were taken for one year. Plasma samples were assayed for testosterone. The size of the testes and the testosterone concentrations in the plasma showed a high correlation. The testis size was reduced (mean length 12 ± 1 mm) and the plasma testosterone concentrations were low (mean 3.3 ± 0.6 ng/ml) from August to December. Both parameters rose gradually until peak values of testis size (mean length 20 ± 0.2 mm) and plasma testosterone concentrations (mean 47.5 ± 2 ng/ml) were reached in April, May and June. In addition blood samples and testes measurements were taken every two weeks from November to April from a group of 12 mature and 9 immature male ferrets which were housed indoors under a simulated natural photoperiod regimen. Animals were sacrificed periodically for histological data. The purpose of this experiment was to compare the processes of recrudescence of the mature and maturation of the immature ferret. These two processes were found to be very similar with respect to the parameters measured and both groups of animals were reproductively competent when the females came into estrus in the spring.