Gastrointestinal nematodioses of zebu calves in the Pantanal Mato-Grossense region, Brazil, III. Paiaguás subregion

Abstract

Continuing epidemiologic studies of the gastrointestinal nematodiosis of Zebu calves in the Pantanal Mato-grossense region, Brazil, the authors studied the natural population of adult nematodes in weaning calves in the Paiaguás subregion during two years, by using monthly faecal egg counts and necropsies. The identified species, intensity and seasonality of infection were discussed in relation to previous results observed in the Nhecolândia subregion. It was verified that flooding of native pastures during certain period in the wet season inhibits development and/or transmission of the infective larvae to calves. Simultaneous grazing of adult with young animals apparently reduced the infection in the young ones. A higher number of immature forms (L₄) was found during the dry season, showing an escape mechanism from the adverse environment. Through parallel observations it was concluded that gastrointestinal nematodiosis can assume serious character in the Pantanal region.