Regulation of emotion in farm animals: focus on neurobiological actors

The interest for emotion in farm animals is motivated by the aim to improve welfare in livestock production. The study of emotions is based on the cognitive capacities of animals to perceive, evaluate and react to their environment. The perception capacity involves different senses, allows the animal to recognize its environment, and not necessarily induces emotion. Emotions are induced by specific situations as novelty, social separation or predator. Moreover, emotional reactions, evaluated by behavioural, endocrine and neurovegetative responses, are modulated by gender, physiological state or some hormones such as melatonin. The brain structures of the neuronal network of emotions are involved in perception, integrative levels and expression of emotional responses. In farm animals, the most studied brain structures are those of the olfactory system for perception, the frontal cortex and amygdala for integration of the environment, the paraventricular nucleus of the hypothalamus for endocrine responses. Other studies hypothesize the role of the brainstem nuclei in neurovegetative responses, and those of the periaqueductal grey for its putative role in behavioural responses and more generally in the coping strategy. In perspective, it is necessary to better understand the development of the neuronal network of emotions in farm animals, especially the effect of early experience, and the cognitive evaluation involved in emotion.