Factors affecting the effectiveness of head-only electrical stunning in sheep

The effects of factors such as the position of the tongs, the presence of w ool, and the wetness of the skin on the efficiency of the head-only stunnin g procedure, and the duration of the periods of unconsciousness and analges ia were studied in lambs. The degree of insensibility was determined from t he evaluation of physiological responses and electroencephalograms. The pro portion of successfully stunned animals was significantly higher (P<0.05) i n the animals stunned with the tongs in a frontal position than in those st unned with them in a caudal position, in the animals stunned with wet elect rodes than in those stunned with dry electrodes and also in the animals wit hout wool than in those with wool. The interval between stunning and sensib ility to pain was affected significantly (P<0.01) only by the position of t he tongs, being longer in animals with them in a frontal position than in t hose with them in a caudal position.