Abstract

Exogenous melatonin has been demonstrated to induce early winter furring in farmed mink and fox. In an exploratory trial implants containing either 0, 4, 8, 12 or 18 mg of melatonin (Regulin. Ltd, Melbourne) were inserted subcutaneously in nine groups of ferrets (farmed fitch). The treated groups each consisted of 12 male and 12 female fitch. Forty four untreated fitch comprised the controls. The implants were administered either in mid-January to 8-week old kits or in mid-February to 12-week old kits. At 14-day intervals, all animals were weighed and the 24 hour dry matter consumption of 3 groups (with 0, 8 and 18 mg melatonin implants) measured. All pelts were graded for size, clarity, quality and colour. The melatonin implants caused a significant increase in feed consumption two weeks after administration accompanied by an increase in weight gains. Appetite and weight gains subsequently increased in untreated fitch and weights at pelting were not significantly different between treated and untreated fitch. Melatonin administered in January caused an early, but limited, development of the winter fur pelage. Many of these animals subsequently developed a new winter coat and pelting time was later than for untreated controls. The February treatment caused an advancement in pelt prime by up to 6 weeks compared with control animals (19 April v 1 June). Quality and size attributes of pelts from treated fitch were comparable to control animals. Differences between the various experimental formulations in their ability to maintain high levels of plasma melatonin for long periods was associated with the occurrence of premature moult in some groups. These data indicate that an optimum melatonin treatment strategy has a role on fitch farms in inducing an early pelt prime with savings in feed and labour and increased management control over pelt processing but that suboptimum treatments are contraindicated for this application.

GK, Barrell, and DF Topp

Proceedings of the New Zealand Society of Animal Production, Volume 49, , 21-24, 1989