Sow enrichment: Keeping pigs busy could improve welfare
By Victoria Kyeiwaa, Prairie Swine Centre
Research on different enrichment materials for pigs has shown that giving appropriate enrichments to growing pigs can result in reduced aggression, reduced fear, improved growth and fewer behavioural vices such as tail-biting. Some commonly used enrichment materials are straw, chains, wood, rope, mushroom compost, wood shavings, garden hose, peat moss and rubber balls.
Although European research has identified straw and other malleable and consumable materials as being optimal, there has been a reluctance to provide such materials in North America.
“Straw has been effective in grower-finisher pigs but there is an increased risk to biosecurity,” says Dr. Jennifer Brown, an ethology research scientist at PSC who is Kyeiwaa’s supervisor. “In this study, we included straw as a comparison treatment to the other enrichments. Small amounts of high fibre materials such as chopped or pelletized straw can be provided in a rack or hopper, for example, and will increase satiety (feeding satisfaction) in sows as well as providing enrichment.”
The sows in the study were offered three options for enrichment materials: rope, small amounts of straw, and wood on chains. A control group received no enrichment materials. Because pigs are social animals in a social environment, subordinate animals may be bullied and driven away from available resources by dominant animals. Thus, the study also investigated the influence of social status on the animals’ use of enrichment materials.
By observing the behaviour of both dominant and subordinate sows, the researchers determined if all sows, irrespective of social status, benefitted from enrichment use. Another common problem with enrichments is that animals lose interest in them over time. Kyeiwaa and the research team also determined whether it is beneficial to provide the same enrichments or if regularly rotating them increases their interest and value to the sows.
“Enrichment can help reduce aggression and stress and improve physiological function
for all ages of animals”
Initial results of this study have shown that sows spend more time in the enrichment area in the mornings after feeding. Both dominant and subordinate sows spent equal amounts of time present in the enrichment area but more dominant sows were observed contacting the enrichments. Sows in the Constant treatment interacted less with enrichments than in the Rotation or Stimulus treatments. This means that sows are more likely to lose interest when the same object is left in the pen continuously. Subordinate sows of parity 1 and 2 were more likely to be victims of aggression, with more lesions observed in this study. Although Dominant sows showed some evidence of greater contact with enrichments, Subordinate sows were also contacting and spent more time lying near the enrichments. There was little evidence of aggression observed and any aggression observed was mostly on day 1 after the enrichments were provided.
“Enrichment can help reduce aggression and stress and improve physiological function for all ages of animals,” says Brown. “Clearly there is a benefit to the industry, and providing enrichment will also help to address consumer concerns about barren conditions in pig housing. Once producers get comfortable with the concept of enrichment, I’m sure we will see them taking the lead on this and coming up with some great ideas.”