Abattoir inspection as early warning system to improve pig welfare at farm level

In the last decade, scientific results emphasised the importance of the meat inspection for animal welfare surveillance by providing early warning and feedback to the farmers, but the contrasting results suggest further investigation on the specific indicators related to herd management. The present study aimed to evaluate whether data collected at the abattoir at post mortem inspection can be used as an early warning of welfare issues at farm level. For 6 months, a total of 906 carcasses, equal to 10% of each batch from 12 intensive commercial farms, slaughtered in 3 different plants in Northern Italy, were included in this study. Relevant animal welfare indicators were selected based on their validity and feasible evaluation during the slaughtering process; then a protocol for visual-only meat inspection was created. Three animal welfare officers were trained in applying the protocol with an online training day. The whole carcass was examined for lesions detectable at the external examination (severe chronic traumatic wounds on the skin, tail lesions, ear lesions, bursitis and deformity of bones of the limbs), and for pathological conditions of internal organs (pericarditis, hepatic milk spots, pleurisy and enzootic pneumonia). For gathering retrospective information about welfare status of farms, early warning thresholds were set according to Dalmau et al. (2016), Kongsted and Sorensen (2017) and Bottacini et al. (2018). In one farm severe chronic traumatic wounds exceeded the limit of 5% (7.1%). For tail-docked pigs, 6 farms overstepped the threshold of 1% of animals affected by tail lesions (min: 3.0% - max: 9.8%) and for ear lesions one farm exceed the cut-off point set on 10% (12.5%). Relating to bursitis and bone deformity, 4 farms for each lesions exceeded the thresholds of 3% (min: 3.1% - max: 10.0%) and 0.5% (min: 10.3% - max: 17.1%) respectively. For pericarditis, 7 farms overpassed the limit of 3% (min: 7.15% - max: 12.5%) and even 6 farms exceed the threshold of 10% of pigs with white liver spots (min: 12.1% - max: 25.5%). Regarding pleurisy, the threshold set on 15% was exceed by 2 farms (18.4% and 25.0%), while 7 farms exceed the threshold of 6.5% of pigs with enzootic pneumonia (min: 7.9% - max: 54.1%). In conclusion, only one farm reported no early warnings, while three farms showed a non-conformity of over 50% of the selected indicators. The findings of this study suggest that these indicators may be used as feedback for farmers to enhance the welfare of animals, by reducing the incidence of these lesions and pathologies. Further research is suggested to investigate the correlation of these indicators with herd management and improving a more standardized animal welfare officer training, including an interobserver reliability test to avoid any subjective judgement.