Effects of an antiandrogen treatment on the antler cycle of male fallow deer (Dama dama L.)

Abstract

Weekly application of the antiandrogen cyproteron acetate (CA) to 3 adult (group 1, treatment starting 3 weeks prior to the rut) and 4 subadult (group 2, treatment starting after the rut) fallow bucks led to premature antler casting after about 9 weeks (group 1) or 16 to 17 days (group 2). Variation in time span between onset of CA administration and induced casting (in late November/early December) is attributed to age- and season-dependent differences in androgen levels before and during the treatment period. Casting surfaces of the antlers were flat. In all bucks, casting was followed by a complete though shortened antler cycle, occurring under short day conditions. In February/March velvet was shed from the antlers, indicating a rise in plasma androgen levels at that time. At time of fraying, antlers exhibited signs of immaturity and were shorter than normal. In the most pronounced case of immaturity, the antlers consisted mainly of cancellous woven bone, revealing that bone remodeling and antler mineralization had not occurred to a larger extent. These observations prove that onset of fraying behaviour does not depend on prior maturation of antler bone or necrosis of velvet. Occurrence of the additional antler cycle in late autumn and winter had no negative effect on subsequent antler formation starting in the following spring.

The structure of pedicle and hard antler bone in the European roe deer (Capreolus capreolus): a light microscope and backscattered electron imaging study

“…; Lincoln, ; Kierdorf et al. , ). This suggests that higher androgen levels inhibit osteoclast formation in the pedicle, which would otherwise occur as a consequence of the death of the antlers due to insufficient blood supply and the attempt of the organism to sequester the dead bone (Goss, ).…”

“…So far, studies on the bone architecture of hard antlers were predominantly conducted in larger species, especially red deer and fallow deer ( Dama dama ; Kierdorf et al. , , ; Rolf & Enderle, ; Chen et al. ; Launey et al.…”

Deer antler regeneration: Cells, concepts, and controversies

“…It has been previously suggested that both osteoclastic activity in the distal pedicle and the onset of antler regeneration are repressed for some months following velvet shedding from the antlers, with high levels of circulating androgens playing a major role in this process (Bubenik, 1983;Kierdorf and Kierdorf, 1992a,b;Kierdorf et al, 1993). Thus, in contrast to limb regeneration in urodeles, which starts immediately after the loss of a limb or limb portion, there is a considerable lag-time between velvet shedding from, and death of, the bony antler and the onset of the regenerative process.…”

Histological structure of antlers in castrated male fallow deer (Dama dama)

“…Castration of male deer carrying hard antlers as well as the administration of substances interfering with testosterone production or inhibiting both testosterone production and its action at the receptor level causes premature antler casting (Wislocki et al, 1947;Lincoln, 1971;Muir et al, 1982;Jaczewski, 1985;Bubenik GA et al, 1987, 2002Goss et al, 1992;Schams et al, 1992;Kierdorf U et al, 1993Suttie et al, 1995). Administration of testosterone or estradiol to males in hard antler postpones antler casting beyond the normal date (Goss, 1968).…”