Equine grass sickness (EGS) is a frequently fatal gastrointestinal neurological disease affecting horses, ponies, and donkeys, with significant animal welfare implications.
Grass sickness is one of the most distressing equine diseases from a welfare perspective. Acute and subacute cases cause severe suffering - gut paralysis, inability to swallow, and profound distress - and humane euthanasia is usually the kindest option. Chronic cases present a different welfare challenge: the nursing care required is extraordinarily intensive, demanding months of hand-feeding, physical support, and emotional commitment from owners and carers. Welfare assessment of chronic cases must be honest and ongoing - early improvements can give way to relapse, and the distress of prolonged illness must be weighed against chances of recovery. For horses that do survive chronic grass sickness, recovery can be complete and quality of life excellent, which makes owner perseverance meaningful but not obligatory.