Androgen Levels and Antler Development in Captive and Wild White-Tailed Deer

Abstract

Blood samples were collected monthly from 5 captive adult male white-tailed deer (Odocoileus virginianus) over a 1-year period. A blood sample was also collected, at immobilization, from each of 55 wild adult (12 months old or older) male white-tailed deer captured over approximately 1 year in southwest Virginia. The antlers of each buck were classified according to stage of development at the time of sampling. Androgen levels and the antler cycles for the captive and wild deer were essentially similar and followed a distinct cyclic pattern. Plasma androgen levels (ng/ml) for the captive and wild deer were highest during November (14.03 ? 2.79 (SE) and 31.23 ? 11.03 (SE), respectively) and lowest during June (0.84 ? 0.14 (SE) and 1.14 t 0.36 (SE)). Androgen concentrations were low and antler growth had commenced and was proceeding rapidly in the velvet from March through July. Androgen concentrations were highest and antlers were hardened and polished during November when does are normally bred in southwest Virginia. By December and January, androgen concentrations had diminished substantially, coincident with the initiation of antler shedding. J. WILDL. MANAGE. 47(2):178-183 Antler growth and development are secondary sex characteristics and as such are under hormonal control. Testosterone has the general effect of promoting and maintaining antler maturation. Certain levels of testosterone secretion are necessary for full ossification of the antlers and death of the velvet (Wislocki et al. 1947). Studies of testosterone concentrations in red deer (Cervus elaphus, Lincoln et al. 1970) and roe deer (Capreolus capreolus, Short and Mann 1966) and with serum testosterone levels in white-tailed deer (McMillin et al. 1974) have shown antler shedding to be related to falling testosterone level, whereas velvet shedding results from a rising level. The white-tailed deer is a valuable trophy animal, so appropriate management should include plans for sustained harvests and suitable trophies. Such a management approach must include a greater understanding of the hormonal relationship involved in the annual reproductive and antler cycle of the male. Previous studies neither considered the hormonal characteristics of captive and wild deer separately, nor provided sample sizes large enough for statistical analysis. Because the relationship between androgens other than testosterone and the antler cycle was never studied, it was important in the present investigation to examine androgens as they relate to the antler cycle. The objectives of this investigation were: (1) to measure monthly variation in plasma androgen levels in captive and wild whitetailed deer and (2) to relate these levels to changes in the antler cycles of the same animals. 1 This study was supported by McIntire-Stennis Project No. 636201. Contribution No. FIW 76-03 from the Department of Fisheries and Wildlife Sciences. 2 Present address: Oregon Cooperative Fishery Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 77331. 178 J. Wildl. Manage. 41(2):1977 This content downloaded from 157.55.39.141 on Mon, 18 Jul 2016 05:49:02 UTC All use subject to http://about.jstor.org/terms ANDROGEN LEVELS IN WHITE-TAILED DEER ? Mirarchi et al. 179 We thank the personnel of the Radford Army Ammunition Plant for their cooperation, and the Virginia Cooperative Wildlife Research Unit for its financial assistance in maintaining the captive animals, and the use of its vehicles. Technical assistance from J. T. Jones, W. Morehead, and H. Lysy is acknowledged.