Studies from the University of Manitoba and Prairie Swine Centre in Saskatoon, Saskatchewan, are identifying and comparing enrichments for sows that could benefit sows in groups. Two studies were conducted, one at the Prairie Swine Centre with sows fed using free-access stalls, and the other at the University of Manitoba using an electronic sow feeder (ESF) system.
“A number of enrichments were tested and compared,” says Jennifer Brown, research scientist with Prairie Swine Centre. “We also compared the behavior of dominant and subordinate sows in the group for their interactions with enrichment.”
Several treatments were given, rotating on a two-week schedule. The treatments included a control with no enrichment provided, a constant enrichment with wood on a chain, a rotating enrichment that switched between wood on a chain, cotton rope or straw, and a stimulus enrichment that was similar to the rotating enrichment but with a bell/whistle.
What did they prefer?
In short, all enrichments were used by the sows, Brown says. However, the straw enrichment was preferred, followed by rope and then wood.
When rope or wood on chains was provided, 4% of sows were interacting with the enrichment on average throughout the day, but when straw was provided, the number of sows interacting with enrichment doubled. This is due to straw having attractive properties (manipulable, consumable), but also because the straw was distributed over a larger area (spread on the solid floor area), allowing more sows to interact at once, she says.
Sows at the University of Manitoba site used enrichments more than at Prairie Swine Centre, which could be because of different genetics, management or feeding systems.
The dominant and subordinate sows had similar enrichment use at Prairie Swine Centre, but at the University of Manitoba the subordinate sows used the enrichments more. Brown says this could be due to the feeding system and dominant sows who may have been 'guarding' the ESF feeding system rather than using enrichments.
Subordinate sows also had higher cortisol levels than dominants, indicating higher stress levels in subordinate animals, Brown adds.
From a producer’s standpoint, Brown says this research demonstrates some practical enrichments that can be provided to sows.
“Object enrichments such as rope and wood on chains are practical, biosecure and have the potential to increase normal behaviors among sows in group housing,” she says.
Sows like to mix it up
The enrichments were changed periodically and designed for easy installation and removal using carabiner clips, Brown says.
“What we found is that by changing the enrichment every few days, there’s a novelty factor that seems to stimulate their interest. That’s a good thing,” says Murray Pettitt, chief executive officer of Prairie Swine Centre.
More research is needed on the effects of enrichment on sow health, Brown adds. However, in younger pigs, many health benefits have been found, including increased growth rate, reduced tail biting, reduced fear responses and improved immune response.
“In sows, we primarily expect to see an increase in positive behaviors (sows are more active and spend time interacting with enrichment) and reduced aggression,” Brown says.