Serum IgE levels in dairy calves: Evaluation of parasite and pasture exposure as possible determinants of IgE response

Immunoglobulin E (IgE) has been regarded as an antibody isotype important in the host response to helminth infection and allergic conditions. Level of parasitic infection has been associated with serum total IgE level and the highest levels have been observed during the spring when environmental allergen levels are also high. Two groups of five parasite-naive calves were maintained in a barn and one of the groups received an experimental gastrointestinal nematode infection. One group of five parasite-naive calves was placed on clean pasture and another group of five was placed on a nematode-contaminated pasture. The contaminated pasture group acquired an acute gastrointestinal nematode infection, compared with a relatively low infection in the experimentally infected group. The only difference between the groups was a significant change (increase) in IgE level in calves on contaminated pasture, compared with the other three groups. This suggested that the infection acquired on pasture and not the experimental infection or environmental allergens encountered while grazing or in the barn stimulated an IgE response.