Influence of body weight and serum electrolyte status on sheep electrocardiography

Abstract

Considering the importance of sheep, economically and in research, it is necessary to explain what normal sheep electrocardiogram values are, and the factors that can cause variations in ECG parameters. The present study, therefore, sought to verify the differences that exist in ECG time scaling between different sub-groupings of sheep. To achieve this, 60 normal sheep were evaluated for the ECG. We reported that at normal ranges of electrolytes and ECG intervals/durations, with mean weights: Ouda = 41.6 ± 7.2 kg (27.8 – 54.0 kg), Balami = 33.2 ± 6.4 kg (22.2 – 43.5 kg); the ewes showed significantly long timing of ECG waves than the rams (P <0.001), the lambs lower than the adult sheep (P <0.001), the Ouda beyond the Balami breed (P <0.001) and the semi-intensive sheep more than the intensively managed (P <0.001). However, when the sub-groups were evaluated for the variations in the PR interval and QTc, with every increase in a unit of the weight, calcium or potassium ions, no discernable difference was noticed between the two sexes. In this, the lambs showed a better slope of these relationships compared to the adult sheep (PR interval: β- coefficient = 0.0010 – 0.0086 v -0.0001- 0.0005 and QTc: 0.0006 – 0.0215 v -0.0001 – 0.0143). The Ouda correlated better than the Balami breed, (PR interval: β- coefficient =0.0062 – 0.2527 v -0.0007 – 0.0033 and QTc: 0.0008 – 0.0264 v 0.0001 – 0.0064). And the semi-intensively managed sheep had an enhanced relationship than sheep managed intensively (PR interval: β- coefficient =0.0002 – 0.0123 v 0.0001 – 0,0071 and QTc: 0.0006 – 0.0197 v 0.0001 – 0.0108). We, therefore, conclude from this result, that within the normal serum electrolytes range, both body weight and habitual physical activity may influence atrial and ventricular depolarization and repolarization timing, with the physical activity level playing an overall dominant role.