Validating and optimizing feedback of Precision Livestock Farming technologies and Meat Inspection to improve welfare and respiratory health in finisher pigs

Currently, the pig industry faces the need for a dramatic reduction in antimicrobial use (AMU) to fight antimicrobial resistance; increasing concerns about emissions of environmental pollutants; and growing societal concerns about pig welfare, with associated increases in legislation. Respiratory diseases and poor welfare are major barriers for the pig industry in meeting these challenges. This thesis focused on the optimization and validation of Precision Livestock Farming technologies and meat inspection data to improve welfare and respiratory health in finisher pigs. The reasoning for this PhD research was the need to connect farmers with the abattoir by creating a feedback loop of information on pig health and welfare. Chapter 2 showed that the prevalence of lung lesions recorded at slaughter was associated with coughs recorded on farm by the cough monitor and by manual quantitative assessments at the end of the finisher stage. In contrast, though coughing was recorded in the earlier weeks of the finisher stage, it was not reflected in a higher prevalence of lung lesions at slaughter. This indicates that respiratory health of pigs in the earlier production stages is not reflected in lung lesions recorded at slaughter. This highlights the benefit of including measures of coughing frequency to complement post mortem findings, to improve the management of respiratory disease on farm. Chapter 3 elucidated information on levels of coughing in healthy pigs which is crucial to calibrate alarm systems for respiratory health - such as the cough monitor used in this study. Furthermore, the work demonstrated the underappreciated influence of ammonia and other environmental risk factors on coughing in pigs. Finally, it emphasised the importance of continuously measuring ammonia concentrations, and the urgent need to integrate sensor technology with ventilation systems to improve pig health. In Chapter 4 we outline the modest predictive power of farm assessments of animal-based welfare outcomes and information on AMU in relation to different meat inspection outcomes (pluck lesions, partial and total condemnations, and low cold carcass weight). The insights gained from chapter 5 are applicable to the current efforts to develop an automated recording tool for routine post mortem meat inspection in the Republic of Ireland, but are also important given the EU focus on measuring animal-based welfare outcomes at slaughter. The optimal simplified pneumonia lesion scoring system involves counting the number of lung lobes affected while excluding the intermediate lobe. This provides the best trade-off between value of information and feasibility. Pleurisy is best evaluated by considering the presence or absence of cranial pleurisy while scoring only moderate and severe lesions in the dorsocaudal region. This thesis represents an important contribution to enhance the sustainability of the pig industry.