The efficacy of pulsed ultrahigh current for the stunning of cattle prior to slaughter

- Pulsed ultrahigh current produces an effective stun of up to 4 minutes duration.
- Stun duration is longer than with conventional stunning and allows delayed exsanguination.
- Variable respiratory, corneal and palpebral reflex activities after the stun is a concern.
- The presence of the reflexes are dissociated with sensibility, and do not predict recovery.

We present results from the development of a new system of reversible electrical stunning of cattle. A single-pulse ultra-high current (SPUC) was generated from a capacitance discharge current spike of at least 5000 V at 70 A, for approximately 50 ms. Ninety-seven cattle were stunned in three experimental protocols. With improvements made to the design of the stun box and charge delivered, 38 cattle were either stunned and immediately jugulated or monitored for signs of reappearance of brain stem reflexes at which point a concussion stun was administered. This use of the SPUC charge, provided as a biphasic-pulse waveform, resulted in a high level of stunning efficacy, with unconsciousness lasting for up to 4 min. These results were supported by EEG data taken from a subsequent cohort of stunned cattle. The SPUC stun also apparently eliminated post-stun grand mal seizures that can occur following short-acting conventional electrical stun, with its associated negative consequences on operator safety and meat quality.