Effect of enrichment on pig vocalizations

The SOUNDWEL project aims to develop a robust vocalisation recognition tool that will allow a fine-tuned real-time recognition of pig emotions in farm living conditions and in slaughter context by using state-of-the-art bioacoustics techniques. The ultimate objective is to develop a practical tool giving farmers a good overview of the emotional state of their animals. Expression (e.g. visual, vocal) and perception of emotional states play an important role in animal welfare. However, accurate tools to scientifically and automatically measure emotions are still lacking, especially for assessing positive emotions. Due to lack of direct access to the subjective component of emotions in non-human animals, cognitive, behavioural and physiological components are used as indicators. It has been suggested that vocal correlates of emotions might be a convenient non-invasive approach to assess welfare. Several studies have provided evidence for vocal indicators of emotional arousal and valence in pigs and other mammals. However, up to now, knowledge allowing the use of vocalisation as a welfare indicator is still limited, specifically because we have little knowledge regarding how positive emotional states effect vocalizations. The first step in achieving the core objective of this project is to build a comprehensive database of pig vocalisations recorded in different emotionally loaded contexts. The aim of the current study is to test the effect of exposing pigs to an enriched test environment on their vocalizations. The study is not expected to cause any distress for the 32 female commercial pigs we aim to use. We use the minimum number of animals we can according to power calculations, house animals in a good environment with fresh bedding and ad lib access to feed and water, check animals twice daily to ensure good health, and use testing and eauthanization procedures that cause minimal suffering or distress.