U. Kierdorf et al., EFFECTS OF AN ANTIANDROGEN TREATMENT ON THE ANTLER CYCLE OF MALE FALLOW DEER (DAMA-DAMA L), The Journal of experimental zoology, 266(3), 1993, pp. 195-205
Weekly application of the antiandrogen cyproteron acetate (CA) to 3 ad
ult (group 1, treatment starting 3 weeks prior to the rut) and 4 subad
ult (group 2, treatment starting after the rut) fallow bucks led to pr
emature antler casting after about 9 weeks (group 1) or 16 to 17 days
(group 2). Variation in time span between onset of CA administration a
nd induced casting (in late November/early December) is attributed to
age- and season-dependent differences in androgen levels before and du
ring the treatment period. Casting surfaces of the antlers were flat.
In all bucks, casting was followed by a complete though shortened antl
er cycle, occurring under short day conditions. In February/March velv
et was shed from the antlers, indicating a rise in plasma androgen lev
els at that time. At time of fraying, antlers exhibited signs of immat
urity and were shorter than normal. In the most pronounced case of imm
aturity, the antlers consisted mainly of cancellous woven bone, reveal
ing that bone remodeling and antler mineralization had not occurred to
a larger extent. These observations prove that onset of fraying behav
iour 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.