Induction of autumn moult in mink (Mustela vison Peale and Beauvois) with melatonin.

Adult female mink, living in natural conditions of temperature and photoperiod, were treated by melatonin implants in mid-July, when the summer coat was in its resting stage. As a result, a moult was induced 5 to 6 weeks before the normal time; its showed the characteristics of an autumn moult as observed by the gradient of hair changes over the body and the high number of hair follicles per bundle (47 p. 100 more than in the summer coat). The winter coats produced in this way were mature in the early days of October, i.e. 6 to 7 weeks before those of the control group.