The effect of slaughtering skills on the welfare of cattle during stunning with a captive bolt

The performance of stunning in various abattoirs can differ. The aim of the study was to compare the stunning of cattle with a captive bolt in two abattoirs. We monitored the slaughtering skills by measuring the deviation of the location of the stunning shot hole on the skull from the ideal point and further by measuring the angle of inclination of the stunning shot on the skull from the ideal perpendicular angle. We observed the impact of different slaughter skills on the quality of stunning of animals based on the occurrence of failure to achieve motor paralysis after a stun shot. The failure to collapse occurred significantly more frequently (P < 0.05) in abattoir A than in abattoir B. In both abattoirs there was a higher (P < 0.05) number of bulls failing to collapse than in females (cows and heifers). However, the effect of slaughter skills on the occurrence of signs associated with insufficient stunning was not found. The signs occurred in abattoir A and abattoir B to the same extent. In bulls, the number of animals with signs was higher (P < 0.05) than in females in both abattoirs. The results show that insufficient proficiency of skills in stunning cattle with a captive bolt leads to a higher number of animals failing to collapse after a stun shot. The effect of slaughter skills on the occurrence of signs in bulls and females was not proven; however, in bulls a higher incidence of signs was demonstrated than in females. Bull, cow, slaughter, stunning effectiveness, welfare Slaughtering of cattle in abattoirs includes, according to the legislation, the stunning of cattle and their subsequent killing by bleeding (European Union 2009). From the welfare perspective, the stunning phase when the animal is deprived of consciousness is particularly important. Subsequent killing takes place when the animal is already unconscious, does not perceive pain and is not exposed to suffering due to environmental and human influences, the presence of other animals in the abattoir or to movement restrictions, changes in body position, and loss of coordination (Atkinson et al. 2013; Terlouw et al. 2016; Kamenik et al. 2019). Stunning of cattle is most often performed using a device with a captive bolt, which causes sudden trauma to the skull, brain, and related blood vessels (Kamenik et al. 2019). The correct placement of the shot leads to the stunning of the animal accompanied by motor paralysis and a fall of the animal in the stunning box. In a properly stunned animal, there should be no signs associated with insufficient stunning of the animal, namely the corneal reflex, reactions to painful stimuli, the attempt to regain an upright posture, vocalization and rhythmic breathing (Gouveia et al. 2009; Atkinson et al. 2013). Stunning quality in different abattoirs may vary and is affected by the qualifications, experience and diligence of the staff performing stunning as well as the companies’ own quality assurance system, e.g. monitoring procedures with regard to stunning effectiveness (Hemsworth et al. 2011; von Wenzlawowicz et al. 2012; Atkinson et al. 2013; ACTA VET. BRNO 2021, 90: 109–116; https://doi.org/10.2754/avb202190010109 Address for correspondence: Prof. Ing. Eva Voslářová, Ph.D. Department of Animal Protection and Welfare and Veterinary Public Health Faculty of Veterinary Hygiene and Ecology University of Veterinary and Pharmaceutical Sciences Brno Palackého tř. 1946/1, Brno 612 42, Czech Republic E-mail: voslarovae@vfu.cz http://actavet.vfu.cz/