Effects of Slaughter Knife Sharpness on Blood Biochemical and Electroencephalogram Changes in Cattle

SIMPLE SUMMARY: The role of knife sharpness in slaughtering animals, from the perspective of animal welfare, is likely subconsciously ignored by the masses involved in the abattoir industry. This might be due to the difficulty in objectively quantifying the sharpness of a knife. Furthermore, a small incremental improvement in sharpness might result in a huge productivity trade-off at the abattoir when the slaughterman needs to dedicate more time to sharpen their blades in between slaughters. This study attempts to assess the effects of sharp and commercial sharp knives on the pain and stress levels of animals. After objectively measuring the sharpness of knives with an ANAGO(®) sharpness tester, animals were slaughtered with commercial sharp and sharp knives. The results obtained from blood and brain activities related to pain and stress revealed that the two sharpness levels had different effects on the stress and pain level in animals, suggesting that the sharp knife produced the least amount of stress and pain in animals compared to those slaughtered using a commercial sharp knife. ABSTRACT: The sharpness of the knife used for slaughter is of the utmost importance from an animal welfare perspective. The quantification of knife sharpness is almost impossible in abattoirs. The sharpness of the knife blade used to slaughter an animal, as well as its effects on animals’ pain and stress levels, is an important area of investigation that needs to be addressed. The objective of this study was to evaluate the effects of knife sharpness on blood biochemical parameters, plasma catecholamines, and electroencephalographic (EEG) responses. Twenty Brahman crossbred steers were either subjected to slaughter with a sharp knife (n = 10) or a commercial sharp knife (n = 10); knife sharpness was measured with the ANAGO(®) sharpness tester. There was significant increase in adrenaline (p < 0.0001), glucose (p = 0.0167), creatinine kinase (p = 0.0123) and lactate dehydrogenase (p = 0.0151) at post-slaughter compared to pre-slaughter in commercial sharp knife group than in thesharp knife group. A significant increase was observed in the median frequency (p < 0.0001) and total power (p < 0.0001) of the EEG, the parameters for pain and stress, in the animals slaughtered with the commercial sharp knife than those slaughtered with the sharp knife. Thus, EEG results also supported the hormonal and biochemical results. From the results, it is concluded that animals slaughtered with a sharp knife experienced the least amount of pain and stress compared to those slaughtered with a commercial sharp knife.