Evaluation of ST-Segment Duration and Morphology of Standard Base Apex Lead Electrocardiograms in Different Age Groups of Apparently Healthy Holstein Cattle

The present study was conducted to obtain electrocardiographic data regarding the values of ST-segment morphology and duration from 84 apparently healthy Holstein cattle in fourteen different age groups from newborn to 7 years old. We recorded electrocardiograms in standard base apex lead system with the paper speed 25 mm/sec. and calibration of 10 mm equal to 1 mV. The morphologic assessments of electrocardiograms showed that all groups had normal isoelectric ST-segment, except newborns. Elevation of ST-segment was detected in 64.2% of newborn calves. The magnitude of this up sloping was 0.10±0.03 mV. The results of the comparison of ST-segment duration among different age groups showed that there were significant differences between the ST-segment duration of newborns (0.11±0.02, sec) and 5 years old (0.16±0.03, sec.), and also between 15 days (0.09±0.03, sec.) and 5 years old (P<0.05). The results of the present study may be accepted as normal ST-segment duration and morphology in different age groups of healthy Holstein cattle which will provide a good basis for judging and interpreting electrocardiograms.