Gastrointestinal nematode diseases of zebu calves in the Pantanal Matogrossense region, Brazil. II. Annual population dynamics of adult nomatodes in calves born at the end of the rainy season

Abstract

The natural population dynamics of adult nematodes in calyes born at the end of the reiny season (1976-1977) in the subregion of Nhecolândia - "Pantanal Matogrossense"- Brazil, was observed, for one year, by using faecal egg counts (E.P.G.), coprocultures and necropsies. Thirty male calves, initially two-to-three months old, were used for this study; they were kept on native pastures and raised under the same extensive management of the region. According to the results obtained, the most common and important genera are: Haemonchus, Oesophagostomum and Cooperia. Calves born at the end of the rainy season (February/March) are intensively infected during the following rainy season; thus, an anti-helminthic treatment is recommended before weaning. The E.P.G. generally showed the fluctuation during the infection intensity, but failed in the estimation of its level.