Zearalenone and its presence in pasture

Abstract

The role of zearalenone, a mycoestrogen produced by soil-borne, free-living fungi, was reviewed for its significance to grazing ruminants, and a pilot survey then conducted in south west Victoria. Zearalenone was widespread in dairy, beef and sheep pasture in the survey conducted during autumnwinter. Zearalenone was present in 80% of 87 randomly selected pastures. The maximum concentration observed was 21 mg/kg DM. For 31% of all pastures, zearalenone exceeded 1.0 mg/kg, the level above which overseas research has suggested that fecundity in sheep may be adversely affected. Within this data set, zearalenone concentration was independent of mean annual rainfall, date of sampling, pasture height and pasture age. Investigations into infertility of livestock should take into account the possible role of mycoestrogens. Their possible additive/synergistic effect with mycotoxins is discussed.