Hard fallow deer antler: A living bone till antler casting?

Deer antlers are the only mammalian bone structures which regenerate comple tely every year. Once developed, antlers are cleaned of the velvet-like ski n. Presently it is believed that due to velvet shedding the blood supply is interrupted in the solidifying antler bone. Histological examinations were made on different parts of fallow deer antlers investigated from the time of Velvet shedding till the antler casting. The present study on hard (poli shed) antlers revealed living bone with regions presenting living osteocyte s, active osteoblasts, osteoid seams and even early stages of trabecular mi crocallus formation, thus indicating to a continuous bone remodeling. A wel l developed vascular system was found despite the presence of hard antler b one. The pedicle bone exhibits a rich supply of capillaries and vessels con nected to the spongy core of the main branch and the compact bone as well. There is evidence that hard fallow deer antlers possess a functioning vascu lar system that "keeps the antler moist" resulting in a high impact resista nce when fights are most frequent. As late as 3 weeks prior to antler casti ng a large number of living cells were discovered within the antler core. A s we have no doubt that parts of the polished fallow deer antler represent a living bone, we have concluded that a sufficient blood supply of the antl er core is maintained almost till the time of antler casting by vessels pas sing through the antler base. (C) 1999 Wiley-Liss, Inc.