Identification of risk factors for production diseases in commercial pig farms through secondary data analyses

PhD ThesisThe aim was to identify risk and protective factors for production diseases in commercial pig farms. Data from on-farm questionnaires and three industry databases holding relevant information were collected and analysed to identify inter-relationships between indicators for production diseases, welfare and performance, and to explore different risk factors for these indicators. The connection of different data sources, combined with the sampling of pig farms to represent the commercial population, proved challenging. However, inter-connections between health, welfare, performance and biosecurity in commercial pig farms in the UK were identified by multivariate analyses. Internal biosecurity scores were generally lower than those for external biosecurity, and little impact of biosecurity was observed on indicators like mortality, prevalence of lameness and pigs requiring hospitalization. Assessment of the UK “Real Welfare” scheme data showed in general low prevalence of welfare issues and demonstrated a reduction in prevalence in 2014, 2015 and 2016 compared to 2013. A risk factor analysis pointed towards the need for attention to pen environment and feeding management across all farming systems. While the provision of substrate was associated with a reduction of prevalence of some welfare outcomes, tail docking on its own did not seem to be effective in reducing tail biting. In commercial pig farms in France, additional analyses were conducted on risk factors associated with piglet mortality, considered as a production disease, utilising a necropsy database. The identification of different mortality patterns and specific risk factors for different categories of perinatal mortality highlighted the necessity for a better understanding of the differences between farm types in order to develop targeted remedial strategies. Additional analyses from a retrospective survey highlighted the positive impact of supporting both suckling and thermoregulation to reduce piglet mortality after birth. Our results illustrated the potential value of secondary analyses to identify factors influencing the production diseases and derive recommendations for their alleviation.Prohealth projec