In most countries the tails of young pigs are docked to prevent tail biting later in life (McGlone et al., 1990). Tail docking is not only painful for the animals; it also conceals the presence of a more chronic animal welfare problem, namely behavioural deprivation and boredom. Several studies suggest that environmental enrichment, especially the provision of straw, reduces the chance of tail biting (Van Putten, 1969) and tail biting behaviour (e.g. Bøe, 1993; Petersen et al., 1995). However, most pig husbandry systems in Western Europe cannot be equipped with large amounts of straw, because this would block their slurry-based manure systems. Other enrichment devices were developed for these systems, such as the provision of iron chains, rubber hoses, car tires and wooden beams. Such ‘toys’ may provide some occupation and reduce general pen mate-directed behaviours (Sambraus and Kuchenhoff, 1992), but the degree depends on the provided materials. Van de Weerd et al. (2003) investigated 74 different enrichment objects during 5 days in order to find the characteristics that the favoured objects had in common. They found that the main characteristics for intense use were; among other things, ingestibility, chew ability and destructability. Zonderland et al. (2003) suggested that a combination of flexibility and destructability might be relevant material characteristics to attract the pigs’ attention. This may help to reduce tail biting as tail biting has been suggested to be redirected exploration behaviour (Van Putten, 1980). Since tail biting was regularly observed among the weaned piglets at the Pig Research Unit of the Animal Sciences Group in Lelystad, the Unit offered a unique opportunity to study tail biting directly. In addition to preventing tail biting, a need exists for more scientific information on curative treatments once tail biting has started to limit the negative consequences of a tail biting outbreak. Therefore, in this experiment the effects of two curative treatments (removing the biter and twice daily straw provision) were tested in pens subjected to four different preventive measures against tail biting (suspended chain, suspended rubber hose, straw rack and twice daily straw provision). Regarding the straw treatments, it was tried to combine partly slatted floors with the provision of small amounts of long straw without blocking the slurry-based manure system. In total, 960 undocked weaned piglets (10 piglets per pen) were observed during 5 weeks. Tail lesions (none, bite marks and wounds) were recorded daily. The incidence of pens with wounded pig tails was significantly lower when straw was provided twice daily (8% of pens) compared to the chain (58% of pens) and rubber hose (54% of pens) treatment, but did not differ significantly from the straw rack treatment (29% of pens). Tails with bite marks were significantly less common in pens with twice daily straw (16% of pens) compared to chain (88% of pens), rubber hose (79% of pens) and straw rack (75% of pens). No significant difference was found between the curative treatments. Both treatments showed a reduced incidence of red fresh blood on the tails at days 1–9 following curative treatment, compared to day 0. However, neither curative treatment eliminated tail biting entirely. In conclusion, this study indicates that tail biting is best prevented with a small amount of straw, provided twice daily, and to a lesser extent with a straw rack, compared to providing a chain or a rubber hose. Once tail biting has occurred, providing a small amount of straw twice daily and removing the biter appears to be equally effective.

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