Proper enrichment for intensively-farmed pigs – From review to preview

Bracke, M.B.M. 2016. Enrichment materials for intensively-farmed pigs – From review to preview (Conference abstract & presentation, ICPD 2016). In: Kemp, B. et al., 2016. 16th International Conference on Production Diseases in Farm Animals. June 20-23, 2016. Wageningen, NL. p. 179.


Tail biting is a well-known production disease in intensively-farmed pigs raising concern for animal welfare, e.g. related to the practice of routine tail docking. To reduce tail biting pigs are provided with enrichment materials. EU legislation requires that pigs have permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities. In order to meet this directive many pigs are provided with a metal chain with or without a rather indestructible object attached to the chain. The European commission recently revised current guidelines as to what constitutes adequate enrichment, apparently moving into the direction of the status-quo in welfare schemes. Building on extensive previous work at Wageningen UR Livestock Research, especially on the modelling of pig enrichment (the so-called RICHPIG model) a review is presented of our current state of knowledge. In addition, an outline is given as to how so-called AMI-sensors, measuring Animal-Material Interactions (AMI) (semi-)automatically, can be used to assess the pig’s need for enrichment, also in relation to aspects associated with health status, such as feed restriction, biting wounds and streptococcus infection. It is suggested that the use of chains with or without rather indestructible materials such as pipes, balls or (hard)wood is generally inadequate to enrich the pens of intensively-farmed pigs. An evolutionary mechanism appears to be underlying the causation of multifactorial welfare problems in general, the issues of enrichment, tail biting and tail docking in pigs in particular. In this respect ongoing selection for increased resource efficiency has been exerting a profound impact on livestock production. Various routes are explored as to how persistent welfare problems may be resolved, including a method that has been called Intelligent Natural Design (IND).

Branched chain
Two organic pigs interacting simultaneously with a branched chain in the snow. Despite access to a straw bed for rooting, even organic pigs may interact with such chains for long periods of time, esp. directed towards the floor. In fact they will root the chain on the floor more than twice as much as playing with it in a horizontal position. In intensive pig production chains are often (too) short, and when a hockey-type ball or ‘sustainable’ plastic pipe is attached to the end of such a chain the pigs’ interest, and their welfare, is often even reduced further. By contrast, to improve the chain further 7mm stainless-steel anchor chains may be recommended for growing pigs over the cheaper c-chain shown here, as anchor chains have heavier and more rounded shackles.

See also an older previous presentation on tail biting.

Bracke, M.B.M, Wolthuis, M., Zonderland, J. J., Kluivers, M., 2011. TAILS TO TELL – Tail docking, tail biting and enrichment for pigs – Experiences from the Netherlands. Herning, DK, May 25-26, 2011.