The aim of this study was to determine the changes that may occur in the heart by electrocardiography according to the degree of anemia in cattle with theileriosis.

This study consisted of 24 cattle with theileriosis (diseased group) naturally infected with T. annulata and 8 healthy cattle (healthy group) from the same region, which was brought to Elazig region and Firat University Veterinary Faculty Animal Hospital Internal Medicine Clinic in 2019-2020. It was carried out on a total of 32 animals at 1-5 years of age. A total of 24 cattle diagnosed with theileriosis were divided into 3 groups (Group 1 mild anemia group, Group 2 moderate anemia group, and Group 3 severe anemia group), 8 in each group according to hematocrit value and erythrocyte count (according to the severity of anemia). In this study, when the ECG examination findings were examined; there were statistically (P≤0.05) increases in T wave amplitude between Group 2 and Group 3 compared to the healthy group. There were significant (P≤0.05) decreases in the other groups compared to the healthy group in terms of P wave, T wave, PQ interval and QT interval duration. In terms of QRS wave duration, statistical (P≤0.05) decreases were recorded in Group 3 compared to the healthy group. In terms of ST interval duration, statistical (P≤0.05) decreases were found in Group 3 compared to the other groups.

As a result, it was concluded that the heart is affected according to the degree of anemia in cattle with theileriosis and this may cause some arrhythmias, especially sinus tachycardia, an increase in T wave amplitude on electrocardiogram (ECG), and a shortening of the duration of the QRS wave, PQ, ST, and QT intervals can be seen.