Full title: Physiological and behavioural characteristics and needs of pigs Sus scrofa domesticus
Requested by: French Reference Centre for Animal Welfare (FRCAW)
Delivery date: 31/10/2023
Context
This thematic dossier from the FRCAW explores the welfare needs of the domestic pig (sus scrofa domesticus) from the animals' point of view. Covering all stages of physical development, it focuses on the physiological and behavioral needs of pigs. The discussion also covers this social animal's cognitive and emotional capacities, which are directly linked to its needs.
This approach complements that of the EFSA 2022 Scientific Opinion on pig welfare, which examines livestock management practices in the most relevant European husbandry systems and identifies the negative consequences for animal welfare that arise at each production stage, suggesting a set of animal-based welfare indicators and making recommendations for the improvement of pig welfare.
Key points
EMOTIONS
Certain behaviours can express negative or positive emotional states in pigs.
In a negative emotional state, a pig may, for example:
- become agitated (move around a lot) or stand still, unable to move (petrified)
- be highly alert (motionless, ears pricked)
- emit long sounds, resembling cries and squeals,. These are very frequent if the emotion is very strong.
In a positive emotional state, a pig may, for example :
- move only a little or not at all (the animal lies down)
- point its ears forward
- emit short sounds, resembling growls and barks. These are very frequent if the emotion is very strong.
NON-SOCIAL COGNITION
Pigs use their cognitive abilities to enable them, in particular, to adapt to their environment and make effective use of food sources.
SOCIAL COGNITION
Pigs live in structured social groups, that require the establishment aand maintenance of a hierarchy. This social organisation means taht pigs must be able to distinguish between familiar animals and strangers and show a preference for familiar individuals.
SOCIAL HIERARCHY
Pigs are extremely sociable, living in highly stable social groups. The hierarchy is based on relationships of dominance/subordination, linked in particular to the age and size of the animals.
Because they tend to upset the hierarchy, weaning and re-grouping are particularly stressful events in a pig's life.
ACTIVITIES
Exploratory behaviour is highly developed in pigs. IT constitutes a need, and is stimulated by novelty.
Exploratory behaviour involves a pig's sense of smell: with its snout, a pig explores its environment by rooting, biting, chewing and nudging/pushing.
A lack of available manipulable materials for a pig is one of the main causes of unwanted behaviors such as tail biting or chewing the ears of other pigs.
Pigs need sufficient space and enrichment to be able to perform strongly motivated behaviours such as exploration, socialisation, resting, playing and avoiding aggressors.
PLAY
Young domestic pigs are particularly playful. Being able to express playful behaviours is essential for the good development of young pigs, to help prevent the appearance of harmful behaviours, and can indicate well-being.
ENRICHMENT
Because of their cognitive, emotional and social capacities, pigs need to be provided with different forms of enrichment:
- Environmental enrichment (manipulable materials such as straw)
- Social enrichment (other pigs/play)
- Cognitive enrichment (stimulation of the cognitive capacities of individual animals in captivity including tasks to perform in their environment)
