Effect of Straw Provision in Racks on Tail Lesions, Straw Availability, and Pen Hygiene in Finishing Pigs

SIMPLE SUMMARY: Pigs spend the majority of their time exploring their surroundings. Unfulfilled exploratory behavior has been linked to tail biting in pigs, leading to decreased welfare and production. Straw provision enables exploratory behavior and reduces tail biting, but large amounts of straw may be difficult to incorporate into current production systems, causing e.g., poor hygiene. This study examined whether provision of straw in racks, rather than on the floor, can enable larger straw rations without compromising hygiene. The study was conducted on a commercial farm with 458 undocked pigs in 42 pens provided with straw in racks or on the floor. Available straw and manual cleaning requirement were assessed daily, and presence of tail lesions was assessed weekly. Compared with pigs in the floor treatment, pigs in the rack treatment had more lesions in the beginning of the production period, but fewer tail lesions at the end. This could be because pigs in the rack treatment initially did not consume straw from the rack, leading to low straw access early in the production period. ABSTRACT: Unfulfilled exploratory behavior in pigs has been linked to tail biting, which causes reduced performance and welfare. Provision of straw can reduce tail biting, but large straw rations can cause poor hygiene in pens. This study examined whether provision of straw in racks, rather than on the pen floor, can enable larger straw rations without compromising hygiene. The study was conducted on a commercial farm with 458 undocked pigs in 42 pens provided with straw in racks or on the floor. Available straw and manual cleaning requirement were assessed daily, and presence of tail lesions was assessed weekly. Both treatments had a low requirement for manual cleaning (Floor: 1.7%, Rack: 1.8%). Pigs in the rack treatment had a higher incidence of lesions early in the production period, which coincided with these pigs initially not consuming straw from the rack, leading to low straw access. Late in the production period, these pigs had learned how to use the rack and had a lower incidence of lesions than pigs in the floor treatment. Delayed use of the rack may have been linked to undeveloped spatial skills in the pigs, which needs further research.