Relationship between agonistic behaviour and propensity to develop excessive drinking and chain manipulation in pigs

Area of Science:

• Animal Behavior
• Ethology
• Neuroscience

Background:

• Individual differences in animal stress responses suggest underlying behavioral and neurological mechanisms.
• Understanding these mechanisms is crucial for animal welfare and management.

Purpose of the Study:

• To investigate the relationship between agonistic behavior in pigs and the development of abnormal repetitive behaviors (ARBs) under restrictive conditions.
• To determine if dominance rank influences the propensity for excessive drinking and chain manipulation in food-restricted pigs.

Main Methods:

• Two groups of 16 food-restricted pigs underwent a group feeding competition to establish dominance ranks.
• Pigs were then housed in either restraint or loose conditions, with half remaining food-restricted.
• Excessive drinking and chain manipulation were monitored, alongside agonistic interactions and dominance scores.

Main Results:

• No housing effects on behavior were observed.
• Only food-restricted pigs developed excessive drinking and chain manipulation, with significant individual variation.
• Pigs with higher dominance scores exhibited significantly increased drinking levels over three months.
• No correlation was found between dominance rank and chain manipulation levels.

Conclusions:

• Agonistic tendencies in pigs, assessed via dominance rank, are linked to the development of excessive drinking under restrictive housing and feeding.
• Excessive drinking and chain manipulation appear to be mediated by distinct behavioral and neural mechanisms.
• These findings highlight the importance of social hierarchy in understanding stress-related behaviors in pigs.