CONICET | Buscador de Institutos y Recursos Humanos

The situation of the gastrointestinal nematodes in organic beef cattle in Canada is unknown. Very few reports have shown the epidemiological patterns of the disease in conventional beef farms in the country; however, whether these patterns can be similar to those in organic farms remains to be proved. Three organic beef cattle farms in the province of New Brunswick, Canada, were visited monthly during the grazing season - May to October /November - 2005 to monitor the development of gastrointestinal nematode disease through faecal parasite egg counts (epg). Faecal samples were cultured to identify the parasitic nematode genera present in the farms. The parasite contamination curves in two of the three farms (Farms B and C) throughout the grazing season was quite similar, showing an early rise and a peak in fecal egg counts in spring-early summer, followed by a decrease towards the end of the summer and early fall. The contamination curve in the third farm (A) shows a different pattern, with very low to almost zero egg counts during the first half of the grazing season followed by a slow but steady increase in the second half. The nematode genera distribution resulted similar in all farms, with Ostertagia sp. being the most prevalent genus (56-68%), followed by Cooperia sp. (17-22%), Trichostrongylus sp. (8-17%), and Haemonchus sp. (4-5%). Oesophagostomum sp. was present on two farms (1-3%), while Nematodirus sp. appeared only on one farm (2%). The present work is the first description of seasonal presence of gastrointestinal nematodes in organic beef herds in Canada, and is based solely on analysis of faecal samples showing contamination patterns. A second year is under way which includes analysis of pasture samples to complete the picture showing both parasite contamination and infectivity patterns.

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