A team of British researchers looked at the causes of tail biting in 92 pork operations across England during an 11-month period. Their findings were published in the Applied Animal Behaviour Science 81. They started with the premise that tail biting is an abnormal behavior of pigs that is thought to have a multi-factorial origin. It is considered an unpredictable event on farms and is hard to reproduce experimentally. They determined that a novel approach, involving a case-control study, was needed to investigate tail-biting risk factors.

At each visit, the researchers interviewed the site’s owner or manager, and inspected the unit. Farms were categorized into those that had tail biting in at least one pig in the past 6 months and those that had not.

Their analysis yielded the following main results:

  • Adding straw in the creep area once or more per day decreased the risk of tail biting by 10 fold.
  • Keeping grower pigs on partially or fully slatted floors versus a solid floor increased the risks of tail biting (odds ratio = 3.2).
  • Using a feeding system with five or more grower pigs per feed space increased the risk of tail biting (odds ratio = 2.7).
  • A stocking density during the growing phase of 110 kg/m(2) or greater increased tail biting risk (odds ratio = 2.7).
  • Farms that belonged to a holding of five or more pig units had an increased risk of tail biting (odds ratio = 3.5).
  • As the number of pens per stockman increased by one, the risk of tail biting increased by 1.06-fold.
  • Tail biting also was associated with the following disease and production information:
  • As the P2 backfat value increased by 1 turn, risk decreased by 1.5-fold.
  • Post-weaning mortality higher than 2.5 percent was associated with a 3.9-fold increase in the risk of tail biting.
  • Respiratory disease was associated with a 1.6-fold increase in risk.
  • Tail docking was associated with a  3 fold increase in the risk of tail biting.

In conclusion, the researchers quantified that some management practices can be changed to reduce the tail-biting risk in grow/finish pigs.