Rejection by pigs of mouldy grain containing deoxynivalenol.

Weaner pigs on a farm near Beaudesert in south eastern Queensland refused to eat feed comprised largely of wheat and barley. Older pigs consumed small amounts and some prepubertal gilts subsequently displayed enlarged and reddened vulvas. Wheat, barley and triticale were grown on the farm during 1983, which was unusually and persistently wet. The wheat and triticale were harvested and stored for about 3 weeks with moisture contents above 14% before being fed. Samples of the wheat and triticale contained pale pink grains, which can indicate infection by the fungus Fusarium graminearum Schw. On analysis 2 mycotoxins known to be produced by F. graminearum were detected, deoxynivalenol (vomitoxin) which causes feed refusal and vomiting, and zearalenone which causes oestrogenic effects. Concentrations of deoxynivalenol in the wheat, triticale and barley were 34, 10, and less than 0.1 mg/kg respectively. Concentrations of zearalenone were 6.2, 2.8 and 0.1 mg/kg respectively. Subsequently, F. graminearum was isolated from grains and crop residues. Although the wet weather contributed to F. graminearum infection of the crops before harvest, most of the toxins probably developed during storage.