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Social space requirements in fattening pigs and the effects of pen-shape. An agent-based approach - Anouk van Spronsen

Space allowance is an important factor affecting animal welfare in fattening pigs because they need space to perform natural behaviour. Social space is the additional space used for interactive activities such as play and aggression. There is little knowledge on social space requirements. The aim of this study was, therefore, to gain more insight in social space requirements of fattening pigs.

Space allowance is an important factor affecting animal welfare in fattening pigs because they need space to perform natural behaviours. Space requirements to perform these behaviours consist of static space, behavioural space and social space. Static space is based on the physical occupied floor space per pig. Behavioural space is the additional space used for individual activities such as feeding, dunging and resting. Social space is the additional space used for interactive activities such as play and aggression. There is little knowledge on social space requirements. The aim of this study was, therefore, to gain more insight in social space requirements of fattening pigs.

A literature study was done to evaluate social space requirements for the most common social space patterns in pigs (huddling, play, aggression and avoidance). No exact estimations on space requirements could be made for these patterns. Avoidance behaviour, however, may minimize social space requirements for aggression, provided, that there are sufficient opportunities to perform avoidance behaviour. An agent-based model (ABM) was developed to identify potential key factors affecting space use patterns in various pen-shapes. The model represented a barren pig pen with 10 pigs showing moving and lying behaviour. Five pen-shapes with equal area surfaces were included: rectangle, triangle, l-shape, square and circle. The effects of pen-shape factors on inter-animal distances, number of social encounters and number of disturbances were explored.

Three factors were identified from literature: maximum distance to avoid (Dmax), perimeter space and number of corners. We found that minimum distance to avoid (Dmin) might be a fourth influencing factor. Resting in corners reduced pen-shape effects for disturbances and inter-animal distances. Based on these factors the rectangular pen-shape should provide the best space use opportunities of all tested shapes. Output for number of disturbances and distance to nearest neighbour confirm that the rectangular pen-shape provides the best space use opportunities, provided, that corners are used for resting.

Student: AR van Spronsen

Supervisor: ing I Boumans, MSc

36 Ects