BackgroundThe English Cocker Spaniel (ECS) is a common family dog in the UK. This study aimed to describe demography, morbidity, and mortality in ECS under primary veterinary care in the UK during 2016 using data from the VetCompass™ Programme. This study hypothesised that the prevalence of aggression is higher in male than female ECS, and higher in solid-coloured than bi-coloured ECS.ResultsEnglish Cocker Spaniels comprised 10,313/336,865 (3.06%) of dogs under primary veterinary care during 2016. The median age was 4.57 years (inter-quartile range (IQR) 2.25–8.01) and the median adult bodyweight was 15.05 kg (IQR 13.12–17.35). The annual proportional birth rate was relatively stable between 2.97–3.51% from 2005–2016. The most common specific diagnoses were periodontal disease (n= 486, prevalence 20.97%, 95% confidence interval (CI): 19.31–22.62), otitis externa (n= 234, 10.09%, 95% CI: 8.87–11.32), obesity (n= 229, 9.88%, 95% CI: 8.66–11.09), anal sac impaction (n= 187, 8.07%, 95% CI: 6.96–9.18), diarrhoea (n= 113, 4.87%, 95% CI: 4.00–5.75), and aggression (n= 93, 4.01%, 95% CI: 3.21–4.81). The prevalence of aggression was higher in males (4.95%) than in females (2.87%) (P= 0.015) and in solid-coloured (7.00%) than in bi-coloured dogs (3.66%) (P= 0.010). The median age at death was 11.44 years (IQR 9.46–13.47) and the most common grouped causes of death were neoplasia (n= 10, 9.26%, 95% CI: 3.79–14.73), mass-associated disorders (n= 9, 8.33%, 95% CI: 4.45–15.08), and collapse (n= 8, 7.41%, 95% CI: 3.80–13.94).ConclusionsPeriodontal disease, otitis externa, and obesity are identified as the most common health issues for ECS, and neoplasia and mass-associated disorders as the most common reasons for death. The prevalence of aggression was higher in males and solid-coloured dogs. The results can aid veterinarians in giving evidence-based health and breed choice information to dog owners and highlights the importance of thorough oral examination and body condition score evaluation during routine veterinary examination of ECS.