Mycotoxins in farm silages - a 2-year Irish national survey

Toxicogenic fungal moulds have been previously identified in Irish farm silages and are known to be capable of producing mycotoxins. Mycotoxins are detrimental to animal health and performance and can be transferred through feed to animal produce. The objectives of this study were to identify and quantify the challenge posed to livestock from mycotoxins in Irish silages and determine whether conventional chemical characteristics could be used as indicators of mycotoxin occurrence. Over the 2-year period, 300 silages were sampled on 150 farms and these consisted of round-baled grass silages (n=115) and pit silages of either grass (n=175) or maize (n=10). There was no significant difference in mycotoxin concentrations across silage types in either year, except for baled silage containing higher concentrations of enniatin B compared with pit silage in Year 1. Conventional chemical characteristics of silages were generally not reliable predictors for mycotoxin incidences; however, dry-matter digestibility, crude protein, fermentation products and ash did predict the incidence of enniatins and beauvericin. The incidence and concentration of the twenty measured mycotoxins were generally low and individual mycotoxin concentrations recorded were considerably lower than current EU directive or guidance thresholds. Non-regulated mycotoxins measured were similar to or lower than concentrations reported in the literature. Based on current knowledge and the concentrations of individual mycotoxins detected in this study, the challenge to Irish livestock and livestock products from animal consuming silage is generally low. However, the additive or synergistic effects of multiple mycotoxins in silage are unknown.