Occurrence of helminths in pig fattening units with different management systems in Northern Germany

The helminth infections an 13 pig fattening farms with different management systems (complete or partial all-in-all-out system or continuous fattening ) in North-Western Germany were investigated over at least three fattening periods. Pooled faecal samples were taken from pens once before and three t imes after anthelmintic treatment. At the beginning of fattening 34.9% of t he samples contained helminth eggs, mainly from Oesophagostomum spp. (27.5% ). Ascaris suum eggs were found in 10.5% of the samples, while other parasi tes were only rarely found. The number of pig-supplying farms was positivel y correlated with the helminth infection prevalence. Immediately after dewo rming, all pen samples were free of helminth eggs, However, the prevalences increased again, and by the end of fattening A. suum was found in 33.0% an d strongylids in 6.0% of the samples. Pens harbouring A. suum-excreting pig s at the beginning of fattening had higher infection levels at the end, and this was also the case for nodular worms. The final prevalence of Ascaris was higher in partial exchange systems than in complete all-in-all-out syst ems and in old pig houses compared to new ones. Transmission of both Ascari s and Oesophagostomum was highest in autumn and winter. Thus, a single anth elmintic treatment at the beginning of fattening could not prevent infectio n during fattening, and the state of infection at the beginning was associa ted with the helminth burden at slaughter. Therefore, the purchase of paras ite-free pigs in combination with appropriate hygiene management may minimi se the initial infection pressure and keep subsequent infection of the herd at a minimum. (C) 2001 Elsevier Science B.V. All rights reserved.