When slaughtering is done carefully cortisol levels in cattle can be substantially lower than farm handling conditions. Tume and Shaw (1992) reported that steers and heifers slaughtered in a small research abattoir had and average cortisol levels of only 15 (ng ml)-1, and cattle slaughtered in a commercial slaughter plant had levels similar to farm handling.When things go wrong the stress levels increase greatly. Cockram and Corley (1991) reported a median value of 63(ng ml)-1. One animal had a high of 162(ng ml)-1. The slaughter plant observed by Cockram and Corley (1991) had a poorly designed forcing pen and slick floors. About 38% of the cattle slipped after exiting the holding pens and 28% slipped just before entering the race. Cortisol levels also increased when delays increased waiting time in the single file race. This was the only study where vocalizations shortly before stunning were not correlated with cortisol levels. This can probably be partly explained by earlier stress caused by the slick floors. Ewbank et al.,(1992) reported the lowest average value. This may be explained by excellent handling before the stunning box.
Beta-endorphin levels, which is another indicator of stress, were not significantly different between the two groups.
For commercial cattle slaughter with a captive bolt stunning the following average values have been recorded:
- (45 ng ml)-1 (Dunn,1990)
- (25-42 ng ml)-1 (Mitchell et al.,1988)
- (44.28 ng ml)-1 (Tume and Shaw,1992)
- (24 ng ml)-1 (Ewbank et al.,1992)