Production performance and pruritic behaviour of pigs naturally infected by Sarcoptes scabiei var. suis in a contact transmission experiment

Reports on the effects of mange on the production performance of pigs are c onflicting. So far, studies have used experimental infections, by depositin g encrusted lesions from chronically infected pigs into the ears of experim ental pigs, However, this is a poor representation of what happens under na tural field conditions. The purpose of our study was to quantify the effect s of sarcoptic mange on production performance and pruritus in pigs that we re infected by contact with S. scabiei vac suis-infected pigs, A total of 8 0 piglets were matched by sex and weight and randomly divided between exper imental and control compartments, In the experimental compartment, each of three naturally S, scabiei var. suis-infested pigs were randomly allocated to three pens with 13 susceptible pigs each. From day 0 to 35, the growth p erformance of pigs in the experimental compartment was significantly (P=0.0 4) worse (35 g/d) than of pigs in the control compartment, From day 35 to 1 12, there was a statistical trend (P=0.10) that the growth performance of p igs in the experimental compartment was lower (50 g/d) than that of pigs in the control compartment, For the complete fattening period (0-112 or more days), the growth performance of pigs in the experimental compartment was s ignificantly (P=0.05) worse (41 gld) than that of pigs in the control compa rtment. Mean feed conversion ratio (kg feed per kg gain) was 2% higher in t he experimental compartment compared with the control compartment, Pigs in the experimental compartment had a nine times (95% CI: 2 - 44) higher chanc e of showing pruritic behaviour than pigs in the control compartment.