According to the Code of Practice for the Care and Handling of Pigs (2014). Enrichment improves animal welfare by enhancing animals’ physical or social environments. Enrichment goals include:
- increase the number and range of normal behaviours
- prevent the development of abnormal behaviours, or reduce the frequency or severity
- increase positive utilization of the environment (e.g. use of space) and
- increase the animal’s ability to cope with behavioural and physiological challenges.
Environments for pigs can be enhanced through methods that span several categories:
- social enrichment – involves either direct or indirect (visual, olfactory, auditory) contact with other pigs
- occupational enrichment – encompasses both psychological enrichment that provides animals with control or challenges (e.g. devices) and enrichment that encourages exercise
- physical enrichment – can involve altering the animals’ enclosures or adding accessories such as objects, substrate or permanent structures (e.g. nest boxes)
- sensory enrichment – visual, auditory, olfactory, tactile and taste stimuli
- nutritional enrichment – involves either presenting varied or novel food types or changing the method of food delivery.
Pigs are initially attracted to materials that are odorous, deformable, and chewable, but for sustained enrichment, the best materials are complex, changeable, malleable, destructible, and are ingestible or contain sparsely distributed edible parts. Enrichment materials and objects need to be monitored to ensure that they do not cause health problems (e.g. strangulation, choking, poisoning, obstruction of the digestive tract, transmission of pathogens) or compromise food safety. While straw is recognized as a premium source of enrichment, it poses challenges to manure management systems.
Enrichment strategies, such as providing objects suitable for chewing and rooting, can deter pigs from harmful social behaviour such as ear and tail-biting and from engaging in stereotypies such as belly nosing and sham chewing.
The revised Code of Practice for the Care and Handling of Pigs includes several changes that impact production practices on Canadian farms, including requirements for the provision of enrichment to pigs at all stages as well as group housing for sows. Multiple studies have shown that providing appropriate enrichments can result in significant benefits to pigs.
Because pigs are highly motivated to explore their environment, enrichment gives them something to root and interact with in the pen environment, and can reduce the manipulation of pen mates. Enrichment benefits include reduced fear responses, reduced aggression and vices, and improved growth. There are multiple enrichment options that can be used such as alternative feed types, pen objects, pen design, or human interaction. Many of these enrichments can be produced on-farm and implemented at low cost.
What environmental enrichment strategies can be incorporated into slatted-floor pen systems for sow groups?
Researchers screened several different enrichment devices, such as hanging wooden blocks, three items hung together (chain, rope and wood block) and straw. They also studied different enrichment strategies, including the constant provision of one enrichment device, the rotation of three enrichment devices and no enrichment
Results showed that enrichment had a positive impact on sow behavior and that all tested enrichment devices can be used with sows. Sows tended to interact more with the devices when they were changed regularly (rotation). Sows tended to prefer chopped straw over the other devices. Straw provides the advantage of being both malleable and consumable, but can be challenging to use due to concerns over manure management and biosecurity.
A follow-up study with fibre enrichments noted that dominant sows had greater access to enrichment, suggesting the more valued enrichment resulted in greater competition. Further investigation is needed to better understand the importance of social status and different forms of enrichment.