Tail biting is known as one of the most serious behavioral problems in domestic pigs. Tail biting causes serious economic loss in pig production and is also an animal-welfare problem. This study examined inexpensive and convenient pig managing methods to relieve tail biting. Piglets (Landrace×Duroc, 35〜60 days old) kept in the Tochigi Prefectural Livestock & Dairy Experimental Center Haga Branch were used for this study. In experiment 1 (Exp 1), the effects of three treatments were tested. In the control, piglets did not receive any special treatment. In the environmental enriched (EE) treatments, piglets were presented with either of four iron chains, plastic chains or cotton ropes to bite, and these materials were interchanged twice in a week. In the NaCl treatment, piglets were given 1.8% sodium chloride solution (salt water) in addition to fresh water. Damage caused by bites to the tails was scored and recorded. In the control, the damage score on the piglets’ tails tended to increase as days went by, whereas those in the EE treatment did not. The damage score in the NaCl treatment decreased after salt water was given. The comparisons among treatments indicate that the increase in damages to the tails in the NaCl treatment was significantly lower than those in the controls. The results of the salivary cortisol levels, which were measured to evaluate stress, indicated that stress decreased in some litters under the EE and NaCl treatments. In Exp 2, we investigated the effects of diet form. Piglets were given either a pelleted (pellet treatment) or crumbled (crumble treatment) diet, and the damage scores for the tails were recorded. Damages to the tails of piglets in the pelleted treatments increased significantly after given a pelleted diet, whereas no increase was observed in those in the crumble treatment. In conclusion, we found that presenting 1.8% salt water could relieve damage caused by tail biting in piglets.

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