Hair loss in deer
Deer replace their pelage (hair coat) twice per year in a process called “molt”. In the spring, they replace their winter pelage and in the late summer/early fall they replace their summer pelage. The summer pelage is red in color and consists of thin, short guard hairs and no undercoat. The winter pelage is gray to dark brown with longer, thicker guard hairs and a fine, wooly undercoat.
During molt, there is a stark contrast between the winter and summer pelage. The pelage no longer appears sleek and it can appear patchy and unkempt.
It can take several weeks for the molt to be complete and pelage replacement usually begins on the head and neck and down the chest, sides and legs. Although normal molt is most commonly the cause of hair loss observed, other conditions such as a bacterial dermatitis, pressure necrosis, trauma, congenital anomaly or very rarely, mange, can cause hair loss. Hair loss in deer in other states has been attributed to exotic lice or winter ticks, but we have not observed hair loss attributed to these parasites in Michigan deer. Normal molt can be distinguished from other conditions by the presence of a normal hair coat underneath the molting pelage or by monitoring the deer, who should be displaying normal pelage within several weeks.
If you are concerned about hair loss in a deer, please contact the Wildlife Disease Lab at 517-336-5030. If you have pictures of the deer we can usually tell by the photos if it is normal molt or something to be concerned about.
Photos of normal molt in Michigan white-tailed deer: