Effect of Testosterone on Antler Growth in Male Sambar Deer (Rusaunicolor unicolor) in Horton Plains National Park, Sri Lanka

Abstract

ABSTRACTThis study establishes the relationship between testosterone concentration with the different antler phases in male sambar deer (Rusa unicolor) inhabiting the Horton plains National Park, Sri Lanka (HPNP). Antler growth of sambar was categorized into seven phases; Cast (C), Growing single spike (GS), Growing into a Y as first tine appears (GIY), Growing Velvet begins to harden as third appears(GVT), Growth completed - velvet shedding begins (VS), Hard antler (HA), Casting (CT) based on phenotypic observations. The fecal samples were collected from 10 male sambar deer in each different phases of the antler growth cycle. Fecal testosterone level was estimated using radioimmunoassay (RIA). The results disclose that the dry feces of sambar deer in hard antler phase have a highest mean testosterone concentration of 18.52± 01.87 ng g−1. In the GVT phase the mean testosterone concentration was 09.50±2.01ng g −1, while in the VS phase the mean testosterone concentration increased to 14 ± 01.89 ng g−1. The study also reveals a declination of the testosterone concentration (06.80± 01.20 ng g-1) in CS phase. The C phase had a mean testosterone concentration of 05.52± 0.84 ng g−1. The fecal testosterone levels of the male sambar deer in HPNP changes according to the phase of the antler cycle.SUMMARY STATEMENTTestosterone concentration in fecal pellets of antler phases of male sambar deer in Horton plains National park, Sri Lanka evaluated by Radioimmunoassay kit. The results obtained in this study were agreement with identical research work carried out in other deer species with temperate ancestry.