Use of organic material provided by an automatic enrichment device by weaner pigs and its influence on tail lesions

Providing pigs with organic enrichment material is important for satisfying pigs' natural explorative behavior to prevent injurious tail biting and thus increase animal welfare in general. The aim of this study was to investigate the effects of automatically supplied enrichment material of three different types (alfalfa pellets, oat bran pellets, or a mixture of both) and different enrichment frequencies (2, 4, or 6 supplies/day) on the behavior, the occurrence of tail biting, and daily weight gains of weaner pigs. The results showed significant effects and interactions of enrichment material, frequency and the time of day on the exploratory behavior, the occurrence of tail biting, and daily weight gains. Higher probabilities for pigs using the enrichment material were observed for groups provided with only two supplies/day or receiving oat bran pellets. Additionally, more pigs explored the material when supplied in the afternoon compared to the morning. Tail lesions began to increase in week 4 of the rearing period. Higher probabilities of having a tail lesion were recorded in groups provided with two supplies/day compared to four or six supplies per day. Furthermore, the highest probabilities for pigs having a tail length loss at the end of the rearing period were shown by groups receiving two supplies/day, with 0.170 for alfalfa pellets, 0.342 for mixture, and 0.486 for oat bran pellets. For daily weight gains, only alfalfa groups differed significantly from mixture groups in the case of two supplies/day. No differences were observed for the other factor combinations. These results showed the potential of an automatic enrichment device supporting pigs in performing their natural exploratory behavior in a conventional housing system. Higher numbers of daily enrichment supplies show beneficial effects to reduce the occurrence of tail biting and tail length losses.