Husbandry management, worm control practices and gastro-intestinal parasite infections of sows in pig-breeding farms in Münsterland, Germany.

A cross-sectional survey was performed on 144 farms randomly selected from 3 breeding organisations in Münsterland, Germany, to obtain representative data on husbandry management, worm control practices and their possible associations with gastro-intestinal parasite infections in sows. Straw bedding was provided in the majority of gestation units; lactating sows were frequently kept strawless. Pasturing of gilts and non-lactating sows were performed in 37% of the farms. Sows were treated with anthelmintics (mainly benzimidazoles, ivermectin or levamisole) in 98% of the farms. The proportions of farmers performing the 'targeted' (mainly prefarrowing) or 'non-targeted' treatment strategy (treatment of all animals several times per year) were similar. Piglets were anthelmintically dosed in only 19% of the farms. Patent infections of sows with Oesophagostomum spp., Ascaris suum, Trichuris suis and Eimeria spp. were detected in 79%, 7%, 8% and 29% of all the farms, respectively. Hyostrongylus rubidus infections were only found in farms with pasturing. The within-farm prevalences of both the strongylid and Eimeria infections were negatively correlated with the herd size but positively with the weaning age. Risk factors for strongylid infections were straw bedding in pens and pasturing. Pasturing was a risk factor for Eimeria infections too. There was a positive association between the time interval to last deworming of sows and strongylid egg counts. However, neither the treatment strategy nor the anthelmintic class used was associated with nematode infections. No relations were found between different cleaning methods in stables and endoparasite infections.

Prevalence of levamisole and benzimidazole resistance in oesophagostomum populations of pig-breeding farms in North Rhine-Westphalia, Germany.

The objective of this cross-sectional study was to estimate the prevalence of anthelmintic resistance in porcine strongylid populations in northern North Rhine-Westphalia. A random, weighted sample of 144 pig-breeding farms, stratified by organisation and herd size, was selected from a total of 706 farms with at least ten sows associated with three breeding organisations. On 61 of all visited farms, no or insufficient strongylid eggs were found in the faecal samples. Eighty-three farms were surveyed for resistance by a larval development test (LDT) using a cut-off concentration of 0.58 microg ml(-1) for levamisole and of 0.0113 microg ml(-1) for thiabendazole. The results indicated resistance to levamisole and benzimidazole in Oesophagostomum spp on one and two farms, respectively. Quantitative LDT showed increased LD50 values of levamisole (0.24 microg ml(-1)) and thiabendazole (0.01-0.015 microg ml(-1)) for these field populations when compared with a drug susceptible laboratory strain of O. dentatum (0.084 microg ml(-1) levamisole; 0.0093 microg ml(-1) thiabendazole). Faecal egg count reduction tests using single standard doses of levamisole and flubendazole corroborated the LDT results. Thus, the prevalence of levamisole and benzimidazole resistance was estimated to be 2-3.5% in sow herds of northern North Rhine-Westphalia. The economic importance of these data is assessed.

Characteristics of a flubendazole resistant isolate of Oesophagostomum dentatum from Germany.

Two controlled tests were performed to investigate the benzimidazole resistance of a nodular worm isolate "GIBZ" from a pig breeding farm in Germany. In Trial I, groups of five pigs, artificially infected with Oesophagostomum larvae isolated from that farm were treated with flubendazole at a single dose of 5 mg kg(-1) bodyweight (BW) or remained untreated. In Trial II, three groups of three pigs each infected with larvae after a further laboratory passage of this isolate were treated with flubendazole either at a single dose of 5 mg kg(-1) BW or at a divided dose of 1.5 mg kg(-1) BW daily for 5 consecutive days, or with fenbendazole at a single dose of 5 mg kg(-1) BW, the fourth infected group remained untreated. The respective doses of anthelmintics were mixed with a small amount of feed and administered to individual pigs in both trials. Fecal egg counts before and after treatment and post-mortem worm burdens 7 days after (last) treatment were examined to assess the anthelmintic efficacies. Only infections with Oesophagostomum dentatum were found in both trials. In Trial I, the mean worm count reduction by flubendazole was 30% as compared to the untreated controls. In Trial II, flubendazole administered at a single or divided dose reduced the mean worm burden by 0 and 85%, respectively, whereas fenbendazole was 100% effective. These results establish resistance to flubendazole in the isolate "GIBZ" of O. dentatum. The failure to reveal side resistance to fenbendazole may be explained by that the currently recommended dose rate of this compound is supra-optimal for porcine nodular worms.