Behavior and performance of pigs grouped by three different methods at weaning

Area of Science:

• Animal Science
• Animal Behavior
• Swine Production

Background:

• Postweaning piglet regrouping can induce stress and aggression.
• Tail biting and fighting are common issues in group-housed pigs.
• Odor masking agents (OMA) are sometimes used to mitigate aggression.

Purpose of the Study:

• To evaluate the effect of different pig grouping strategies on agonistic behavior.
• To assess the efficacy of an odor masking agent (OMA) in reducing aggression during piglet regrouping.
• To determine the impact of grouping and OMA on pig performance.

Main Methods:

• 384 crossbred pigs were housed in nursery pens under three grouping treatments (8-1, 4-2, 1-8).
• An odor masking agent (OMA) was applied either before or after mixing.
• Agonistic behavior was observed, and average daily gain and feed intake were measured.

Main Results:

• Combining pigs from different litters significantly increased fighting.
• OMA application had minimal and temporary effects on fighting, with a slight increase when applied before mixing.
• Neither OMA nor grouping strategy affected average daily gain or feed intake.

Conclusions:

• Social mixing of unfamiliar pigs increases aggression but does not compromise growth performance.
• The tested odor masking agent is ineffective in reducing pig fighting or improving performance.
• Management strategies should focus on minimizing social stress during regrouping.