THE EFFECT OF CAGE ENVIRONMENT AND AD-LIBITUM FEEDING ON THE CIRCADIAN-RHYTHM, BEHAVIOR AND FEED-INTAKE OF FARM MINK

The effect of cage size and nest box environment on circadian rhythm a nd on stereotyped and non-stereotyped activities was measured for 66 f armed female mink fed ad libitum. The behaviour of the animals was rec orded over 24 h on video in the months of September and October. Weigh t and feed consumption were measured for the 66 females and the 66 mal e mink placed with the females. The experiment included three cage siz es (0.10, 0.27 and 1.10 M2) and cages with and without nest boxes. In the cages with nest boxes the use of wire netting cylinders and shelve s was evaluated. Farm mink, fed ad libitum, had their primary activity period from 04:00 to 10:00 h. There was no food anticipatory activity , but the actual feeding at noon caused an interruption of the animals ' resting period. Mink in cages without nest boxes performed more ster eotyped behaviour than mink with nest boxes. There was no effect of ca ge size on the measured behavioural elements. Mink were passive for mo re than 70% of the day and night and preferred to rest together. Apart from resting in the nest box, mink preferred to rest on shelves above floor level. Lacking the possibility of using a nest box and performa nce of stereotyped behaviour increase the feed intake of farm mink. A large variation between animals, having a significant effect on all th e measured behavioural elements, indicates different coping patterns a nd/or stress sensitivity.