Pig organ lesions recorded in different abattoirs: A statistical approach to assess the comparability of prevalence

Abstract

Documented lesions of slaughtered pigs provide a high-density data-pool that could be valuable for the purpose of animal health monitoring and breeding. However, data quality and structure hamper the application of statistical methods. The present study provides an approach that enables statistical analysis and evaluates the comparability of lesion prevalence among abattoirs. The German Quality and Safety database provided data of recorded lung, pleura, liver, and heart lesions. Filter criteria were used to improve the data structure. Data of n = 8,004,769 animals, recorded in nine abattoirs over a period of 18 months, were analyzed. Lesion prevalences were successfully modeled by applying a generalized linear mixed model. To examine prevalence differences, the coefficient of variation (CV) on a six-monthly basis was calculated, and a grand mean test (GMT) of significance was applied. High variations in estimated prevalence occurred on abattoir, six-monthly and organ basis. The highest variation occurred in the lung (CV = 64.7%), whereas liver lesions showed the lowest variation (CV = 21.8%). The GMT enabled the visualization of these variations between abattoirs, organs and over time. Concerning the assessment of the comparability of prevalences, it provides a promising tool to monitor changes in lesion examination and to address divergent abattoirs.