A retrospective study of 143 cases of ventricular septal defects in cattle aged under 12 months.

To identify factors that influence the severity of clinical signs associated with ventricular septal defect (VSD) in calves, the clinical and pathological findings of 143 confirmed cases in animals under 12 months of age were retrospectively reviewed. Observed clinical signs included emaciation (92.3%), reduced vitality (83.9%), respiratory signs (77.6%), anorexia (74.1%), exercise intolerance (69.9%), cyanosis or pallor (50.3%), standing with assistance (32.9%), collapse (14.7%), death prior to euthanasia (11.9%), and signs of congestion (7.7%). Cardiac murmurs were detected in all cases and holosystolic murmurs in 86.0% of cases, while ejection murmurs, other systolic murmurs, and diastolic murmurs were detected in a small number of cases. The 143 cases were divided into two groups, the severe group (66 cases) and the mild group (77 cases), based on clinical scores, and their findings were compared. Statistically, there were no significant differences between the two groups in hematological parameters and the diameter of the septal defect. However, the blood urea nitrogen levels were significantly higher, and total cholesterol concentrations were significantly lower, in the severe group than in the mild group. In addition, the prevalence of concurrent malformations, including double outlet right ventricle, pulmonary stenosis, and patent ductus arteriosus, was significantly higher in the severe group than in the mild group. Although the defect diameter in the severe group (median: 2.0 cm) was larger than that in the mild group (median: 1.5 cm), the difference was marginal (P=0.0517).