Which affiliative behaviour can be used as a valid, reliable and feasible indicator of positive welfare in horse husbandry?

It is now widely accepted that good welfare is not simply the absence of negative experiences, but rather is primarily the presence of positive experiences such as pleasure. However scientific investigation of positive emotions has long been neglected. This paper addresses two main issues: first, it reviews the current state of scientific knowledge that supports the existence of positive affective states in animals and, second, it suggests possible applications of this knowledge that may enhance quality of life under animal management conditions. In the first part of the paper, recent advances in psychology and neuroscience are reviewed to provide pragmatic frameworks based on cognitive processes (such as positive anticipation, contrast and controllability) for further investigations of positive emotions in animals. Thereafter, the neurobiological bases of positive emotions are highlighted in order to identify behavioral and physiological expressions of positive experiences in animals. Monitoring both the autonomic nervous system (via heart rate and its variability) and the immune system could offer relevant tools to better assess emotional states in animals, complementary to classical adrenocortical measures. In the second part of the paper, useful strategies for enhancing positive experiences (such as physical, social and cognitive enrichment or putative genetic selection) are outlined. Then this paper emphasizes practical applications for assessing and promoting positive emotions that may help in providing animals with a better quality of life. Play, affiliative behaviors and some vocalizations appear to be the most promising convenient indicators for assessing positive experiences in laboratory and farm animals under commercial conditions.

Simple Summary The Five Freedoms were formulated in the early 1990s and are now well recognised as highly influential in the animal welfare arena. However, a marked increase in scientific understanding over the last two decades now shows that the Five Freedoms do not capture, either in the specifics or the generality of their expression, the breadth and depth of current knowledge of the biological processes that are germane to understanding animal welfare and to guiding its management. For example, this paper refers to some negative experiences that can never be eliminated, merely temporarily neutralised, because they are essential for eliciting behaviours upon which the survival of the animal depends. In addition, it refers to other negative experiences that relate to an animal’s responses to living in poor environments which require improvement, and also to how such experiences may be replaced by positive ones when particular improvements are introduced. For animals to have “lives worth living” it is necessary, overall, to minimise their negative experiences and at the same time to provide the animals with opportunities to have positive experiences. These observations have implications for reviewing and potentially updating minimum standards in codes of welfare. The paper ends with an up-to-date characterisation of the principal features of animal welfare, expressed largely in non-technical terms. Abstract The Five Freedoms have had major impact on animal welfare thinking internationally. However, despite clear initial statements that the words ‘freedom from’ should indicate ‘as free as possible from’, the Freedoms have come to be represented as absolute or fundamental freedoms, even rights, by some animal advocate and other groups. Moreover, a marked increase in scientific understanding over the last two decades shows that the Freedoms do not capture the more nuanced knowledge of the biological processes that is germane to understanding animal welfare and which is now available to guide its management. For example, the named negative experiences of thirst, hunger, discomfort and pain, and others identified subsequently, including breathlessness, nausea, dizziness, debility, weakness and sickness, can never be eliminated, merely temporarily neutralised. Each one is a genetically embedded element that motivates animals to behave in particular ways to obtain specific life-sustaining resources, avoid or reduce physical harm or facilitate recovery from infection or injury. Their undoubted negativity creates a necessary sense of urgency to respond, without which animals would not survive. Also, the temporary neutralisation of these survival-critical affects does not in and of itself generate positive experience. This questions the commonly held assumption that good animal welfare will result when these internally generated negative affects are minimised. Animals may also experience other negative affects that include anxiety, fear, panic, frustration, anger, helplessness, loneliness, boredom and depression. These situation-related affects reflect animals’ perceptions of their external circumstances. Although they are elicited by threatening, cramped, barren and/or isolated conditions, they can often be replaced by positive affects when animals are kept with congenial others in spacious, stimulus-rich and safe environments which provide opportunities for them to engage in behaviours they find rewarding. These behaviours may include environment-focused exploration and food acquisition activities as well as animal-to-animal interactive activities, all of which can generate various forms of comfort, pleasure, interest, confidence and a sense of control. Animal welfare management should aim to reduce the intensity of survival-critical negative affects to tolerable levels that nevertheless still elicit the required behaviours, and should also provide opportunities for animals to behave in ways they find rewarding, noting that poor management of survival-critical affects reduces animals’ motivation to utilize such rewarding opportunities. This biologically more accurate understanding provides support for reviewing the adequacy of provisions in current codes of welfare or practice in order to ensure that animals are given greater opportunities to experience positive welfare states. The purpose is to help animals to have lives worth living, which is not possible when the predominant focus of such codes is on survival-critical measures. Finally, an updated characterisation of animal welfare that incorporates this more accurate understanding is presented.

Simple Summary This review outlines the latest in a succession of updates of the Five Domains Model, which, at each stage, incorporated contemporary verified scientific thinking of relevance to animal welfare assessment. The current update includes, within the structure of the Model, specific guidance on how to evaluate the negative and/or positive impacts of human behaviour on animal welfare. Persons whose actions may be evaluated include, but are not limited to, livestock handlers, owners of draught animals, veterinary care staff, pound/shelter staff, zoo-keepers, wildlife managers, hunters, researchers, companion animal owners, owners of sport/recreational animals, animal trainers and service animal handlers. Situations where human–animal interactions may have negative welfare impacts include: when animals have had little or no prior human contact, when human presence adds to already threatening circumstances, when human actions are directly unpleasant, threatening and/or noxious, when humans’ prior actions are remembered as being aversive or noxious and when the actions of bonded humans cause unintended harms. In contrast, situations where human–animal interactions may have positive welfare impacts include: when the companionable presence of humans provides company and feelings of safety, when humans provide preferred foods, tactile contacts and/or training reinforcements, when humans participate in enjoyable routine activities or in engaging variable activities, when the presence of familiar humans is calming in threatening circumstances and when humans act to end periods of deprivation, inhibition or harm. The explicit delineation within the Model of the potential impacts of human interactions on the welfare of animals enhances the Model’s utility. Additional updates in this latest version are also explained. Abstract Throughout its 25-year history, the Five Domains Model for animal welfare assessment has been regularly updated to include at each stage the latest authenticated developments in animal welfare science thinking. The domains of the most up-to-date Model described here are: 1 Nutrition, 2 Physical Environment, 3 Health, 4 Behavioural Interactions and 5 Mental State. The first four domains focus attention on factors that give rise to specific negative or positive subjective experiences (affects), which contribute to the animal’s mental state, as evaluated in Domain 5. More specifically, the first three domains focus mainly on factors that disturb or disrupt particular features of the body’s internal stability. Each disturbed or disrupted feature generates sensory inputs which are processed by the brain to form specific negative affects, and these affects are associated with behaviours that act to restore the body’s internal stability. As each such behaviour is essential for the survival of the animal, the affects associated with them are collectively referred to as “survival-critical affects”. In contrast, Domain 4, now named Behavioural Interactions, focusses on evidence of animals consciously seeking specific goals when interacting behaviourally with (1) the environment, (2) other non-human animals and (3) as a new feature of the Model outlined here, humans. The associated affects, evaluated via Domain 5, are mainly generated by brain processing of sensory inputs elicited by external stimuli. The success of the animals’ behavioural attempts to achieve their chosen goals is reflected in whether the associated affects are negative or positive. Collectively referred to as “situation-related affects”, these outcomes are understood to contribute to animals’ perceptions of their external circumstances. These observations reveal a key distinction between the way survival-critical and situation-related affects influence animals’ aligned behaviours. The former mainly reflect compelling motivations to engage in genetically embedded behavioural responses, whereas the latter mainly involve conscious behavioural choices which are the hallmarks of agency. Finally, numerous examples of human–animal interactions and their attendant affects are described, and the qualitative grading of interactions that generate negative or positive affect is also illustrated.