The effect of current frequency during waterbath stunning on the physical recovery and rate and extent of bleed out in turkeys

Abstract

Two experiments were carried out to evaluate the influence of the frequency of a sinusoidal stunning current (150 mA, 4 s) on the physical recovery of turkey hens and toms and on the rate and extent of blood loss. In the first experiment, physical recovery of 72 hens and 78 toms was estimated after stunning with one of five different frequencies. The incidence of cardiac arrest after stunning at 50, 300, 480, 550, and 600 Hz was, respectively, 100, 60, 30, 30, and 0% in hens and 53, 38, 0, 0, and 0% in toms. In hens, time to return of corneal reflex and neck tension and the onset of wing flapping decreased as frequency increased. In contrast to hens, about half of the toms stunned at 50 Hz did not show cardiac arrest. In these animals, recovery after 50 Hz was significantly longer than recovery at the four other frequencies. In the second experiment, 50 hens and 53 toms were bled out by a unilateral neck cut 10 s after stunning with one of four different frequencies (50, 300, 480, and 600 Hz). The rate and extent of blood loss within 3 min, relative to live weight, increased as stunning frequency increased. Large differences in the rate and extent of blood loss were observed between turkeys stunned at 50 or 300 Hz, according to the occurrence of cardiac arrest: cardiac activity was associated with significantly higher rate and extent of blood loss in both sexes. Overall, the results suggest that the duration of unconsciousness decreases as stunning frequency increases.