Limitations of Spatial Judgment Bias Test Application in Horses (Equus ferus caballus)

Living the good life? A systematic review of behavioural signs of affective state in the domestic horse (Equus caballus) and factors relating to quality of life. Part I: Fulfilment of species-specific needs

The welfare of horses involved in sport and leisure activities has come under increasing scrutiny, both from within the equine sector and from the public. A systematic review of scientific evidence was conducted to derive observable, evidence-based behavioural measures of positive or negative affective state and factors relating to quality of life in the domestic horse (Equus caballus). Two separate searches (including the terms 'emotion/affect', or 'stress') were conducted, with 179 articles being retained. In Part I of this two-part review (companion paper published simultaneously), articles relating to the extent to which the species-specific needs of the horse are fulfilled in the home environment (n = 21), in relation to social grouping (n = 20), and during weaning (n = 14) were reviewed. Experimental tests of affective state in relation to housing and management (n = 8), and studies relating to stereotypical behaviour (n = 7) were also included. Opportunities for behavioural expression were dependent upon the provision of social and physical resources. Withdrawn or agitated behaviours in situ, avoidance behaviour during handling and agonistic intra-species interactions were indicative of negative affective state. Affiliative intra-specific social interactions, and forage ingestion were considered positive signs. For horses to live a good life, their need for space, companionship, and forage must be prioritised from birth and throughout their lives.

Living the good life? A systematic review of behavioural signs of affective state in the domestic horse (Equus caballus) and factors relating to quality of life. Part 2: Horse-human interactions

Quality of life is dependent upon the extent to which behavioural needs are met, and the balance between pleasant and unpleasant lifetime experiences. In Part II of this systematic review, articles (n = 109) relating to horse-human interactions were reviewed to identify behavioural evidence of their positive or negative impact on the horse. The number of articles (n = 22) relating to the recognition of pain in horses, indicated the importance of identifying health issues, which are also likely to increase the aversiveness of interactions. These and articles relating to emotional reactivity testing in horses (n = 19), the behaviour of horses during handling and management procedures (n = 17), behaviour of the horse when ridden (n = 17), non-procedural horse-human interactions (n = 13), horse behaviour during transportation (n = 12) and behaviour during training other than when ridden (n = 9) were reviewed. During most interactions, horse behaviour is controlled and/or restricted by the human, masking negative or positive signs, and may be confounded by factors including fear and individual differences. In situations involving freedom of movement, positive experiences of horses with humans were associated with approach behaviour, negative ones with avoidance, but training could affect both. Undoubtedly, change is needed to reduce the extent to which interactions with humans are unpleasant for the horse. Only when the needs of the horse are fulfilled and interactions with humans are predominantly pleasurable will their quality of life improve.

Knowledge of lateralized brain function can contribute to animal welfare

The specialized functions of each hemisphere of the vertebrate brain are summarized together with the current evidence of lateralized behavior in farm and companion animals, as shown by the eye or ear used to attend and respond to stimuli. Forelimb preference is another manifestation of hemispheric lateralization, as shown by differences in behavior between left- and right-handed primates, left- and right-pawed dogs and cats, and left- and right-limb-preferring horses. Left-limb preference reflects right hemisphere use and is associated with negative cognitive bias. Positive cognitive bias is associated with right-limb and left-hemisphere preferences. The strength of lateralization is also associated with behavior. Animals with weak lateralization of the brain are unable to attend to more than one task at a time, and they are more easily stressed than animals with strong lateralization. This difference is also found in domesticated species with strong vs. weak limb preferences. Individuals with left-limb or ambilateral preference have a bias to express functions of the right hemisphere, heightened fear and aggression, and greater susceptibility to stress. Recognition of lateralized behavior can lead to improved welfare by detecting those animals most likely to suffer fear and distress and by indicating housing conditions and handling procedures that cause stress.