RESEARCHERS from Scotland's Rural College (SRUC) have been awarded £580,000 to study possible ways to reduce pig aggression in order to improve animal welfare and the economic benefits to farmers.
The team will look at the way pigs fight, specifically how they settle contests upon first meeting.
Pig aggression is difficult to tackle and can cause a major reduction in growth rates, an announcement said. Fighting among animals increases significantly when they are mixed in unfamiliar groups, and mixing occurs several times throughout a pig's life.
"Pigs are going to be mixed over the course of their lives a number of times. Changing that is just not practical, so over the years, researchers have tried to change the pigs' environment, adapting it so they will react less aggressively when mixed," according to Simon Turner, SRUC senior researcher who is leading the project. "However, these changes, such as adding straw, mixing the animals at night and tranquilizing them, have not worked in the long term."
Pigs have a strict social hierarchy. When they are mixed with unknown animals, they need to form this hierarchy, resulting in aggression. The researchers believe that if they can determine how the pigs think, how they assess their fighting abilities and whether they can make sensible decisions on when to give up, practical ways can be found to manage pigs that will reduce aggression.
"Humans are able to assess both their own fighting abilities and those of their attacker," Turner said. "There is evidence that some species can do one or the other, but not both. We know little about how pigs make decisions on who to fight and when to give up, but this knowledge will probably prove to be essential in designing management systems that are effective in reducing the welfare and economic costs of aggression."
Therefore, the key to reducing aggression could be allowing pigs to form their natural hierarchies in as painless a way as possible, making them far calmer during mixing.
"We need to help pigs realize when it would be sensible not to engage in aggression because their opponent is likely to beat them," Turner said.
One area of investigation includes whether mixing pigs at a younger age could reduce their aggression when mixed later in life.
In separate work, the researchers will also explore how much a pig's genetics factor into how aggressive they are and whether selective breeding could help address the issue.
Turner said, "At the end of these projects, we hope to be able to offer better advice on how to manage and breed pigs in ways that will help the animals make the best decisions for their own welfare and, so, reduce aggression."
The U.K.'s Biotechnology & Biological Sciences Research Council has funded the project.