Unlike horns in cattle, antlers are cast off every year. Deer or cervids such as caribou, reindeer, wapiti and moose grow antlers while cattle or bovids, including mountain goats, bighorn sheep, bison and pronghorn antelope, possess horns. Reindeer and caribou are the only cervid species in which both the male and female produce antler.
Antlers begin to grow at about 2 to 3 weeks of age. Growth is determined by a combination of juvenile maturity and threshold body weight. Within one year of age, the pedicles will growth their first antler, usually a single spike. With increasing emphasis on good management and good breeding programs multi-branch spikes with brow lines are becoming more common. The pedicle is distinguished from the velvet antler by a zone of transition in hair style and colour. This zone of transition is not very clear in yearlings and care must be taken not to damage the pedicle when removing the antler by accidentally cutting too low.
The annual cycle of antler casting, antler growth and hardening or calcification is regulated by changes in daylight length, calving (for females) and testosterone levels (in males). Through spring and summer, the antler develops and grows, turning into hard antler usually around the end of August. This is when they will �shed� the velvet from the antler.