Effect of exogenous melatonin on winter fur growth in ussuriansis raccoon dog (Nyctereutes procyonoides ussuransis)

Abstract

The effect of exogenous melatonin on winter fur growth in raccoon dog were investigated during 1993–1995. In the field trials, a total of 496 raccoon dogs were embedded subscutaneously melatonin implants that were made in laboratory for Endocrinology and Reproduction, College of Wildlife Resources. The trial results showed that melatonin was involved in regulation of seasonal molting in ussuriansis raccoon dogs, and promoted effectively the winter fur growth, when raccoon dogs received melatonin treatment at the time near solstice. The date of winter fur maturity were advanced to middle or end of October, about four or five weeks earlier than controls, when male or female pup raccoon dogs were treated with silastic implants containing 8.6mg, 12mg or 15mg melatonin on July 6 and July 11 respectively. The date of winter fur maturity were advanced to late September and early October, about six to eight weeks earlier than controls, when female adult raccoon dogs were treated with silastic implant containing 10.6mg, 12mg or 15mg melatonin on June 4 and June 15 and June 22 respectively.