The Five Domains of Equine Welfare

Equine welfare is an evolving discipline shaped by advances in animal science, veterinary medicine, and ethics. For veterinary professionals, a comprehensive understanding of welfare frameworks and their applications in clinical and management contexts is essential.

Horses are highly adaptable, yet their welfare is contingent upon how well their biological, behavioural, and psychological needs are met.

The Five Domains model offers a structured and evidence-based approach that helps practitioners identify areas of compromise while also promoting positive welfare states. This article examines each domain in detail and integrates real-world examples that demonstrate the application of welfare principles in practice.

Nutrition remains one of the most influential determinants of equine welfare. Horses evolved as grazing herbivores, adapted to consume small amounts of fibrous forage almost continuously throughout the day. Deviation from this feeding pattern, particularly through diets excessively reliant on cereals and concentrates, is strongly associated with gastrointestinal dysfunction, gastric ulceration, metabolic disorders, and behavioural pathology.

The Henneke Body Condition Scoring system, introduced in the early 1980s, provides a reliable and objective method for evaluating body condition. Horses are assessed on a scale from 1 (emaciated) to 9 (obese), with most individuals ideally maintained between 4 and 6 to balance health, athletic performance, and reproductive efficiency (Henneke et al., 1983). Veterinary professionals play a central role in advising owners on diet formulation, not only to prevent malnutrition but also to mitigate risks of obesity, insulin resistance, and laminitis.

Physical health forms a cornerstone of welfare assessment. Preventive care, including vaccination, routine dentistry, hoof care, and parasite control, should be viewed as non-negotiable aspects of welfare management. Pain, disease, or injury not only reduce physical wellbeing but also profoundly affect behaviour and emotional state, making the detection of subclinical issues a priority.

Veterinary practitioners must also consider how advances in diagnostic technologies can complement traditional clinical examination. Objective gait analysis systems, thermal imaging, and wearable biosensors now enable earlier detection of pathology, often before clinical lameness is evident. The integration of these tools into routine practice enhances welfare by reducing the duration of suffering and enabling more targeted interventions.

3. Physical Environment: Designing Systems to Support Welfare

The physical environment is a critical determinant of both physical and psychological wellbeing. Horses require environments that offer appropriate shelter from weather extremes, safe footing, adequate ventilation, and sufficient space for movement. Restrictive stabling without regular turnout has been repeatedly linked with respiratory disease, musculoskeletal stiffness, and the emergence of stereotypic behaviours such as weaving, crib-biting, and box-walking (Cooper and Albentosa, 2005).

Veterinarians play a vital advisory role in assessing whether stabling and management systems meet welfare needs. Attention must be given not only to structural design but also to factors such as social contact, substrate quality, and enrichment. Interventions that restore opportunities for natural movement and social interaction often yield rapid improvements in welfare and reduce the need for pharmacological or behavioural therapies.

Horses are inherently social animals that rely on affiliative bonds within groups for security and psychological stability. Denial of opportunities for social interaction, such as through prolonged isolation, frequently leads to anxiety, aggression, or the emergence of abnormal behaviours. Welfare science increasingly applies systems thinking to behavioural problems, recognising that management practices, environment, diet, and human–horse interactions all interact to influence behaviour (Hausberger et al., 2021).

Veterinary practitioners should approach behavioural issues holistically, recognising that what appears to be a training or temperament problem may, in fact, stem from husbandry systems or underlying health concerns. Interdisciplinary collaboration with behaviourists, trainers, and caregivers can provide sustainable solutions that prioritise equine welfare.

The mental domain is central to the Five Domains model, acknowledging that good welfare encompasses not just the absence of suffering but the presence of positive affective states. Horses are sentient beings capable of experiencing comfort, pleasure, play, curiosity, fear, and frustration. Management systems and training practices directly influence these emotional states, with aversive methods, excessive isolation, or unpredictable routines contributing to chronic stress.

Veterinary practitioners should encourage owners to view emotional wellbeing as an essential welfare component. This involves promoting positive reinforcement training, providing predictable routines, and enabling horses to experience agency and control in their environment. Educational interventions are particularly valuable in bridging the gap between scientific knowledge and owner perception.

Veterinarians are uniquely positioned to operationalise welfare assessment at both individual and population levels. The use of structured frameworks such as the Five Domains checklist ensures that all aspects of welfare (nutrition, health, environment, behaviour, and mental state) are systematically evaluated during consultations (Mellor and Beausoleil, 2015).

Beyond the individual level, welfare frameworks are increasingly being adopted at industry scale. New Zealand Thoroughbred Racing, for example, has applied Five Domains principles across the sector, ensuring that welfare is embedded throughout the lifespan of racehorses, from breeding through to retirement (Mellor et al., 2020). Veterinary involvement in these initiatives not only safeguards welfare but also enhances public trust in equine industries.

Equine welfare is multidimensional and requires simultaneous attention to nutrition, physical health, environment, behaviour, and mental state. These domains are deeply interconnected, and compromise in one inevitably affects the others. Veterinary practitioners are central to ensuring that equine welfare is both protected and advanced, through preventive medicine, evidence-based interventions, and owner education.

The integration of the Five Domains model into daily practice moves welfare assessment beyond the simple prevention of harm. It facilitates the active promotion of positive experiences, strengthening the quality of life for horses and reinforcing the human–equine bond that has shaped our shared history for millennia.