Influence of resources on pig aggression and dominance.

Relationships between presence of feed and water and aggressive behaviour and correlations between dominance and use of these resources were investigated in 64 five to eight week old pigs (Sus scrofa ). Pens of four randomly-selected pigs were established. Social dominance order was obtained largely within the first four hours but aggressive behaviour reached zero 19.4 hours after regrouping four pigs. Whether feed or water were present, pigs fought at similar levels. Pigs who were more aggressive did spend more time drinking water when resources were limited. Pigs that headed the aggressive dominance order did not gain preferred access to resources when they were in limited supply nor when they were abundant.