Incentive mechanisms for liver lesion control in finishing pigs in the Netherlands.

Liver lesion prevalence in slaughtered finishing pigs in the Netherlands remained relatively high from the mid-1990s until 2004, although sufficient measures existed to control the main cause, an infection with the roundworm Ascaris suum. In July 2004 a new incentive mechanism was installed to induce finishing pig producers to increase control of A. suum infections. This paper compares the effectiveness of two Dutch incentive mechanisms: a collective insurance - in place prior to July 2004 - and a reduction in producer payment for each delivered pig with a liver lesion - in place from July 2004. Liver inspection data of pigs slaughtered in 2003-2006 by a major Dutch slaughter company were analysed with an out-of-sample dynamic forecast test and non-parametric bootstrapping. Results showed that after introduction of the price reduction, mean liver lesion prevalence decreased from 9 to 5%. A reduced liver lesion prevalence ranging from 0 to 46 percentage points was observed on 67% of 1069 farms that delivered both during the insurance and the price reduction. The number of farms with a liver lesion prevalence of 5.0% or less increased from 52 to 68%. The price reduction for each pig with a liver lesion was a more effective incentive mechanism to induce finishing pig producers to control A. suum infections than the collective insurance.