Physiological Effects of Electrical Stunning and Venesection in the Fowl

Abstract

SUMMARY Experiments were performed to investigate the physiological effects of electrical stunning and jugular venesection in the fowl. In anaesthetized birds, stunning caused bradycardia, fluctuations in blood pressure, reduction in respiratory rate and elimination of electrocortical activity. Tachycardia and hyperventilation occurred during recovery. Venesection under these conditions produced a rapid fall in arterial blood pressure. In unanaesthetized birds, stunning alone abolished the electrocorticogram within 15 sec. and there followed a gradual recovery after a 1/2 min. of silence. There was bradycardia and an increased depth of respiration, but a decrease in respiratory rate. Venesection alone in unanaesthetized birds caused electrocortical arousal, followed by the elimination of fast activity before the final onset of electrical silence after 21/2 min. Tachycardia occurred initially, but within one minute there was an abrupt drop in heart rate which coincided with the elimination of fast low voltage activity in the electrocorticogram. There was intermittent struggling. Stunning, followed by venesection, resulted in the abolition of the electrocorticogram and there was no return before death occurred from haemorrhage. There was a greater transient tachycardia than normally occurred during recovery from stunning alone.