Cattle welfare assessment at the slaughterhouse level: Integrated risk profiles based on the animal's origin, pre-slaughter logistics, and iceberg indicators

Detection of on farm and transport animal welfare problems at slaughterhouse level is a key issue for the meat industry; however, usually, the assessments do not include basic aspects of animal health. For that reason, it is necessary to develop an assessment method that has an integrative scope and identifies the risk profiles in animals. Therefore, the aim of the present study was to detect cattle welfare indicators that can be implemented at the slaughterhouse level and to develop integrated risk profiles based on the animal's origin, pre-slaughter logistics, and animal-based indicators. We recorded the origin, commercial category, transportation details, and horn size of 1040 cattle upon arrival at the slaughterhouse. Cattle welfare was measured based on individual scores for vocalizations, stunning shots, carcass bruises, meat pH, severe hoof injuries, and organ condemnations. To characterize operational and logistic practices from the farm to the slaughterhouse, a two-step cluster analysis was applied to the aforementioned variables (production system, cattle type, horn size, journey distance, vehicle type), which identified four clusters: small feedlot and free-range profile (C1, n = 216, 20.8 %), feedlot profile (C2, n = 193, 18.6 %), culled dairy cows profile (C3, n = 262, 25.2 %), and free-range profile (C4, n = 369, 35.5 %). The animal's diet and environmental conditions might have influenced the development of hoof disorders in C1 animals (P = 0.023), the proportion of animals that were re-shot was highest in C2 animals (P = 0.033), and C3 and C4 animals were most likely to suffer injuries such as severe bruising (P = 0.001). In addition, the number of stunning shots, meat pH, carcass bruises, severe hoof injuries, and liver condemnations, explained a significant variation in the incidence of various health and welfare consequences based on an animal's origin, which confirmed their importance as 'welfare iceberg' indicators. The study provided detailed data that can be included into assessment methods for the welfare of slaughter cattle, which can be tailored to specific production systems.