The prevalence of irregularity in rhythm and heart sound in apparently healthy small ruminants

This study was conducted on 384 clinically healthy sheep and goats from farms around Tehran suburb. The animals were divided into two equal groups (according to species) and then assigned into three age groups, two gender groups and female animals into two groups: late pregnant and non-pregnant. Heart sounds were auscultated by two cardiologists and heart rate and probable murmurs were recorded. Using the base-apex lead, the electrocardiograms were taken. Three types of dysrhythmias including sinus tachycardia, sinus arrhythmia and atrial premature complex were observed. Regarding the incidence of dysrhythmias, there were significant statistical differences between the age and sex groups, but not between pregnant and non-pregnant animals. The mean heart rate of sheep and goats with sinus arrhythmia was significantly lower than those with regular cardiac rhythm (p<0.001). The prevalence of the murmurs in sheep and goats, which all were systolic, were 6.3% and 8.9%, respectively. Only one holosystolic murmur was detected in a sheep and the others were early to early-mid systolic murmurs. One murmur was detected with grade 3/5 in sheep and other murmurs were grade 1 and 2. The number of murmurs on the mitral valve was higher in age groups 1 (< 6 months) and 2 (6-12 months) compared to group 3 (> 12 months). But there was no significant relationship between the incidence of murmur and age, gender and pregnancy. The results of this study revealed that small ruminants have lower prevalence of dysrhythmias and murmurs compared to cattle and horses.