Prevalence of nematodes in Danish industrialized sow farms with loose housed sows in dynamic groups.

The aim of this study was to investigate the prevalence of nematodes in sows and gilts in modern pig herds which practiced loose housing of sows and gilts. Seventy hundred and ninety fecal samples were examined from seventy-nine farms. Oesophagostomum spp. was found in 15% of farms and Ascaris suum was found in 76% of the farms. Trichuris suis was found in a very few instances. No other nematodes were found. The prevalence of Oesophagostomum spp. within an infected farm was approximately 50% and the prevalence of Ascaris suis within an infected farm was approximately 30%. Housing procedure, farm size and the degree of contact with feces could not be correlated to prevalence on a farm level. It was concluded that in modern sow farms with loose housing systems A. suum and Oesophagostomum spp. are sufficiently prevalent to be considered a threat to productivity.