A STUDY OF ELECTROCARDIOGRAPHIC PATTERNS IN A POPULATION OF COMMERCIAL BROILER-CHICKENS

A study was completed to characterize the electrocardiographic (ECG) p atterns of male broiler chickens. Data were collected from 300 commerc ial broilers. ECG readings were collected from all birds between 12 an d 15 days of age and then twice more at 10-day intervals. The measurem ents included heart rate and rhythm, QRS complex duration, amplitude a nd mean electrical axis (MEA), incidence of ascites and incidence of s udden death syndrome (SDS). Eight birds died from SDS and 4 birds died from ascites. Twelve birds were condemned for ascites at the processi ng plant. The overall population heart rate declined with age. Birds t hat died of SDS had a higher heart rate, whereas those that developed ascites had a lower heart rate than the remainder of the population. T he normal MEA was found to be between 0 degrees and 180 degrees. On av erage 30% of birds showed left or right QRS axis deviation, and this p attern was observed in 14 of the 16 birds that developed ascites. Seve ral types of cardiac arrhythmias were observed, the most common being premature ventricular contractions (PVC). The incidence of PVC increas ed with age, ranging from 1% at 12-15 days of age to 8.9% at 32-35 day s of age. QRS axis deviation was present in 5 SDS birds. It is conclud ed that some 30% of the broiler flock rested was at risk of developing heart failure or heart-related disease.