Feed restriction and tubes for environmental enrichment in growing mink—Consequences for behaviour and welfare

• Published in: Applied animal behaviour science 2011-11, Vol.134 (3), p.193-200
• Main Authors: Hansen, Steffen Werner, Møller, Steen Henrik, Damgaard, Birthe Marie
• Format: Article
• Language: English
• Subjects: Behaviour; energy intake; environmental enrichment; Feed restriction; foods; fur; Fur characteristics; hunger; ingestion; mastication; Mink; motivation; obesity; plastics; restricted feeding; stereotyped behavior; Stereotypy; temperament; Tubes for enrichment; urine; weaning
• ISSN: 0168-1591; 1872-9045
• DOI: 10.1016/j.applanim.2011.06.014

This experiment compared the behaviour of mink during two different feeding routines; slightly restrictive (‘food free period’ of 6 h) or standard (‘food free period’ of 2 h), respectively, and the mink's use of two different types of occupational material; an attached tube made of wire mesh and a shorter loose tube made of plastic, respectively. The behaviour of the mink was observed by scanning on 2 days in weeks 4, 10, 14, and 18 after weaning. On the first day, the mink were observed every hour from sunrise to sunset and fed at normal feeding time (13:00 h) but on the second day the feeding time was postponed to 15:00 h and the behaviour was registered once an hour from 12:00 h until 14:00 h inclusive. The daily feed ratio, live body weight, behaviour, temperament, and fur quality were measured. The results indicate that a slightly restrictive feeding, based on 6 h ‘food free period’, is difficult to practise because mink increase their eating speed and thereby maintain their energy intake and body weight. The mink were not able to compensate for a ‘food free period’ of 12 h, which may cause the feeling of hunger measured as increased stereotypic behaviour during postponed feeding and a more aggressive temperament. However, restrictive feeding may be profitable for the health of mink by reducing the occurrence of the obesity related illness wet belly (urine leakage). It is concluded that 6 h ‘food free period’ is not a feasible management tool for reducing the deposition of fat in mink but 12 h ‘food free period’ increases stereotypic behaviour, which may indicate reduced welfare due to an enhanced feeding motivation. The two types of enrichments did not affect the fur-quality differently and neither the stereotypies. The mink used the attached tubes more than the loose ones, which may have reduced the locomotive activity, but the welfare implication of the reduced activity is ambiguously. None of the two types of enrichments seem valuable for reducing the occurrence of fur chewing in mink.