Happy ending to tails of young pigs in enriched environment

Study shows welfare issue makes financial sense – and it doesn’t take much to get right

Tail biting is both a welfare and an economic issue, and the numerous risk factors which cause the problem means it is difficult to manage.

Access to suitable enrichment materials is known to be one of the most important risk factors, and there is growing pressure to enforce not only the ban on routine tail docking but also making sure suitable enrichment materials are provided.

The first EU legislation regarding enrichment was produced 25 years ago and in 2008 the updated and more comprehensive Pig Directive specified that there should be “permanent access to a sufficient quantity” of material to enable proper investigation and manipulation activities. The 2016 recommendations give more guidance about enrichment materials being “edible, chewable, investigable and manipulable” and should be “of sustainable interest”. So how can this be achieved in fully slatted systems?

Our project focused on finding feasible solutions to manage tail biting in undocked pigs housed in fully slatted systems, mainly by providing manipulable materials and high dietary fibre.

These “environmental enrichments” are crucial because pigs have the natural instinct to forage, and suitable enrichment keeps them from directing these behaviours onto other pigs, such as biting tails. Loose straw bedding is considered the most effective, but when the flooring system is slatted, providing bedding becomes impractical, and therefore we need other alternatives.

We first investigated whether wood is a suitable enrichment material for pigs. Docked pigs were used to assess similar conditions as in most British and Irish farms. We compared different species of wood (spruce, Scots pine, larch and beech) provided to the pigs as posts. The results showed that spruce attracted more interactions from pigs since it is softer without many knots.

When comparing the wood species with a commercially available rubber floor toy, the spruce and rubber toy occupied pigs for a similar amount of time.

Next, we started to rear undocked pigs on fully slatted systems, with one enrichment item (the spruce or rubber toy (EasyFix)) per 14 pigs with either high or standard dietary fibre. There was a high level of tail biting regardless of which enrichment pigs used or what level of dietary fibre they had.

Pigs fed with higher dietary fibre performed more tail biting and had slightly worse lesions. Their faeces became softer because of the fibre, which soiled their hindquarters. When the environment is relatively barren, increasing the dietary fibre is not enough to control tail biting in undocked pigs.

Later we used multiple enrichment items that are all compatible with slatted floors, including an elevated rack with fresh cut grass, hanging wooden blocks, rubber toys and fabrics, wooden posts in dispensers and some floor toys. All pigs had the same eight enrichment items per 12 pigs, but different frequencies of replenishing the items were assessed to find a balance between pigs’ needs and production cost. Half of the pigs were also provided with some hanging items once a week after birth during lactation. Although some level of tail biting still occurred, the percentage of pigs with severe injuries (eg amputated tails or removal for treatment) was much lower than in the previous study.

Pigs with the most frequent enrichment replenishment performed damaging behaviours less frequently and grew faster in the finisher stage compared to those with the least replenishment.

This work shows that enrichment is indeed crucial in managing tail biting, and it was possible to keep tail biting in undocked pigs at a manageable level on fully-slatted floors.

Multiple enrichment for pigs including rubber toys and wooden posts helps to reduce the incidence of tail biting.