Degenerative Valvular Disease in the Cavalier King Charles Spaniel: Results of the UK Breed Scheme 1991–2010

Background Cavalier King Charles spaniels ( CKCS s) are predisposed to degenerative mitral valve disease (DMVD) and studies have indicated a genetic cause. Animals A total of 8,860 CKCSs were examined at shows or private clinics from 1991 to 2010. Objectives To analyze the effects of a breed scheme for CKCS on the age at which a murmur consistent with DMVD was first detected. Methods The presence or absence of a murmur consistent with mitral regurgitation was noted and age a murmur was first detected recorded. Results A total of 16,887 examinations were performed on 8,860 dogs. The median age dogs developed a murmur were slightly younger in male than female dogs (7.8 versus 8.3 years, 95% confidence interval [ CI ] 7.4–8.1 versus 8.0–8.4, P < .001) and cardiologists detected murmurs in younger dogs than did general practitioner ( GP ) veterinary surgeons (7.2 versus 8.6 years, 95% CI 7.0–7.4 versus 8.3–8.7 P < .001). In bitches examined by GP vets during the study, there was a significantly increased age of detection of murmurs over time (8.6–9.2 years, 95% CI 8.3–9.1 and 8.5–10.9, P = .001) but not for male dogs examined by GP vets or dogs of either sex examined by cardiologists. Conclusions and Clinical Importance This study suggests that the age incidence of murmurs associated with DMVD might be increased by application of breeding guidelines based on auscultation alone. This benefit was only seen in a subgroup and compliance of breeders with this voluntary scheme was poor.