Electrocardiographic Parameters in Apparently Healthy Nigerian Indigenous Chickens in Enugu State

Electrocardiography provides objective data on cardiac electrical activity and is a valuable diagnostic tool for identifying rhythm disturbances, conduction abnormalities, and cardiomegaly in avian species. Nigerian indigenous chickens, adapted to local disease pressures and management conditions in the South East zone, are widely raised in Enugu State for meat and egg production. However, normal electrocardiographic reference values for this ecotype have not been established in published Nigerian literature. This study determined electrocardiographic parameters in 40 apparently healthy adult Nigerian indigenous chickens using a standard six-lead electrocardiograph with a paper speed of 50 mm/s and sensitivity of 10 mm/mV. Animals were manually restrained in dorsal recumbency and electrodes were placed on the wings and legs in a standardised manner. Parameters measured included heart rate, P wave amplitude and duration, PR interval, QRS complex duration, QT interval, R wave amplitude, and mean electrical axis. Mean heart rate was 320 beats per minute with a range of 270 to 380 beats per minute. P wave duration averaged 0.024 seconds. Mean QRS duration was 0.018 seconds. The mean electrical axis was positive in leads II and aVF, indicating a leftward axis in the frontal plane. These values differ from those reported for commercial broilers and layers, highlighting the importance of breed-specific reference data for electrocardiographic interpretation in Nigerian indigenous chicken populations. Keywords: electrocardiography, indigenous chicken, Enugu, heart rate, reference values.