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The present study aimed to assess the economic impact of PMWS and PCV2 subclinical infections (PCV2SI) at farm level and to estimate the resulting cost to the industry.
A disease model simulated the varying proportions of pigs in a batch that will get infected with PCV2 and develop either PMWS or be subclinically infected, depending on the farm PMWS severity level. Empirical data from farm and animal level studies were used to fit the model. It generated six outcomes: infected pigs with clinical PMWS that die (PMWS-D); infected pigs with clinical PMWS that recover (PMWS-R); PCV2SI that die (PCV2-D); PCV2SI that reach slaughter age (PCV2-S); healthy pigs (H-S); and healthy pigs, infected or noninfected by PCV2, that die due to non-PCV2 related causes (H-D).
The economic impact of a PMWS-D pig was estimated to be £82.7 (80.0 to 84.4), £27.2 (16.2 to 23.4) for a PMWS-R pig, £84.85 (80.0 to 89.7) for a PCV2-D pig and £13.9 (3.72 to 25.8) for a PCV2-S pigs. The greatest proportion of negative economic impact was due to subclinical pigs. Farm profits became negative at a PMWS severity score of 9 (8.5-9.5). Overall, the economic impact of PMWS for the English pig industry, prior to the introduction of PCV2 vaccines, was estimated to be £61.4 million per year (38.2 to 88.2). The variables with the highest impact in the model, in order of importance, were; a) ‘Post-weaning mortality’, b) ‘pig prices per kilogram deadweight’ and c) ‘number of pig born alive per sow per year’.
This was the first study to use empirical data to model the cost of PMWS nad PCV2SI at different farm severity levels. The model showed the high cost PMWS has caused the English pig industry in 2008 and highlights the importance of the cost of subclinical cases, usually understimated.
P. Alarcon, J. Rushton, B. Wieland. Cost of post-weaning multi-systemic wasting syndrome and PCV2 subclinical infection – a stochastic economic model. IPVS, 2012.
