Relationship between stress-related exsanguination blood variables, vocalisation, and stressors imposed on cattle between lairage and stunning box under conventional abattoir conditions

Abstract

Physiological and behavioural reactions of cattle to handling procedures in a commercial abattoir (electrical prodding actions and duration of the animals׳ stay in the stunning box) were evaluated and set in relation to sex, breed type, and carcass weight. A total of 192 cattle comprised of 45 bulls, 61 steers, and 86 heifers from different breed types (30 dairy breed, 70 beef breed, and 92 crossbreds) were observed from lairage to slaughter during one day. The frequency of electrical proddings and the waiting time in the stunning box was recorded for each individual. As a measure of a behavioural stress response, the number of vocalising animals was recorded. Exsanguination blood serum samples were analysed for cortisol, glucose, and lactate concentrations. Forty-nine animals received no electrical prods; 117 animals were prodded one to three times, and 24 animals received between 4 and 9 prods. Thirteen per cent of all animals were recorded as vocalisers. There was a trend (P=0.07) that heifers vocalised more than bulls and steers. Mean levels per ml of blood were 77.2ng cortisol (SE=68.8), 5.7μmol glucose (SE=1.3), and 6.7μmol lactate (SE=3.3). Cortisol concentrations were lower in bulls than in steers and in heifers (P<0.01), and concentrations above 90ng/ml were measured in 21.3% of the steers and 27.8% of the heifers, but not in the bulls. Lactate and glucose concentrations were not influenced by sex. Breed type had no influence on any of the stress-indicating traits. Prodding categories were not related with concentrations of the blood variables and the number of vocalising animals. A longer stay in the stunning box led to increased cortisol concentrations (P<0.05), but had no influence on lactate and glucose concentrations or on the number of vocalising animals. In conclusion, stress levels were relatively high in the present case, but it was not possible to relate the stress indicators unequivocally to the potential factors of influence investigated.