Development of a microwave stunning system for cattle 2: Preliminary observations on behavioural responses and EEG.

Abstract

DTS: Diathermic Syncope® (DTS) is a novel system for rendering animals insensible prior to slaughter, utilizing microwave energy to induce a rise in temperature in the brain to a point at which the animal is expected to lose consciousness. During development and optimisation of the system, two trials were carried out utilizing non-anaesthetized adult cattle, to gather data on behavioural outcomes and EEG changes following energy application. In trial1, ten cattle received DTS treatments (high energy >290\u202fkJ, n\u202f=\u202f3; low energy <200\u202fkJ, n\u202f=\u202f4; and intermediate 200\u202f<\u202f290\u202fkJ, n\u202f=\u202f3), and seven received captive bolt stunning, prior to exsanguination. In trial 2, following improvements to the efficiency of energy delivery, 20 cattle received DTS (200-360\u202fkJ). Post treatment EEG was characterized by seizure-like activity and reductions in 95% spectral edge and median frequencies; with EEG suppression persisting for at least 80\u202fs up to over 4\u202fmin post treatment application. Animals showed: Loss of posture, Loss of corneal responses; Loss of withdrawal response (pinprick); Eye staring, not following movement. The animals remained unresponsive to stimuli for up to 4\u202fmin post DTS, and behavioural expression of distress was not observed. Seventeen of the 30 animals showed indications of returning reflex responses after 100\u202fs post treatment, suggesting that animals receiving lower energy applications may recover from the stun.