Effects of 'Five freedoms' environmental enrichment on the welfare of calves reared indoors.

We provided comfortable resting areas in pens and tools for self-grooming and suppressing aggressive behavior for environmental enrichment in Japanese black and Japanese Shorthorn calves. At the start of the experiment, the black calves (n = 10) were 164 days old and 138 kg in weight, and the Japanese Shorthorn calves (n = 10) were 176 days old and 164 kg in weight. Calves of each breed were divided into two groups (the enrichment group and the non-treatment group), and each group was housed in a 4 m x 7.2 m pen. The effect of enrichment on calf welfare was estimated on the basis of daily weight gain and behavior. The brush stimulated the grooming behavior in calves although the mean time of using the brush decreased during the experiment. The partition of the feed trough and the wooden wall in the pen decreased the agonistic behavior in Japanese Shorthorn calves (P < 0.01) and increased the affiliative behavior in Japanese black calves (P = 0.08). The cleanliness of the bedding increased sternum lying and lying with the head touching the flank or ground in Japanese black calves and decreased the standing resting behavior in both breeds (P < 0.05 in all the cases). However, the treatments did not have an effect on daily weight gain. We concluded that the treatments would improve the welfare of calves and function as environmental enrichments.