Posted: May 31st, 2010 - 11:21am

When pig health consultant, David Burch, first looked at the financial modeling of Post-weaning Multisystemic Wasting Syndrome (PMWS) there was relatively little data. Treatment and control trials had only been carried out on swine farms that had been severely affected. In those days a typical 6% mortality from the causal PCV2 virus produced around a 6 kg reduction in
average liveweight gain in finisher pigs. Now that more trial data has accumulated - covering mild herd infections as well as severe disease outbreaks - a different picture is emerging. In a new review he considers the data from ten PCV2 vaccine trials, covering 50,000 pigs in North America
and the European Union.
This metadata study reveals that unvaccinated growing pigs in infected herds with no actual deaths from disease, still  lose an average of 2.5 kg in liveweight in comparison to vaccinated piglets.
As the mortality rate increases by 1%, the average liveweight in surviving pigs decreases by approximately 0.5 kg, so that at a 6% mortality rate from PMWS [PCV2 infection] a pork producer not only loses 6% of finisher pigs but also suffers depressed production of 5.5 kg [average per pig] in the survivors. These production losses can be explained by the severity of organ damage to the pigs due to PCV2 viraemia, plus the fact that fighting this virus infection uses up energy that should have gone into growth.
The Octagon Services consultancy has created a free Cost/Benefit Calculator for pig farmers considering vaccinating against PMWS - a syndrome now more commonly referred to as PCVAD [Porcine CircoVirus-Associated Disease]. The calculator begins with trial data based on costings in Euros, but users can input their own data in any currency.
David Burch's latest review, and the online interactive calculator, can be accessed at www.pighealth.com/circovirus.htm