Annual variations in fecal androgen metabolites and antler cycle of captive red brocket bucks (Mazama americana) in southeast Brazil

Abstract

Annual variations in fecal androgen metabolites (FAM) and antler cycle were analyzed in six red brocket bucks exposed to a natural photoperiod in southeast Brazil. Fecal samples and antlers status data were collected weekly during a 1-year period. Four animals were in hard antler throughout the year, whereas one individual cast antlers in September and other took several months to completely shed antler velvet. Monthly means (+/- SEM) of FAM concentrations exhibited no differences in all monitored bucks (P > 0.05). In addition, FAM levels from four males that kept hard antlers year-round were grouped by month and no differences among monthly means were found (P > 0.05). Comparisons between FAM levels at different antler stages were not possible because of the low number of males presenting changes in antler status. These findings indicate that red brocket bucks present no annual pattern in androgen secretion and antler changes, suggesting that testicular and antler cycles in this species are little or not affected by photoperiodic cues.