Exposure of horses to biotoxins, phytoestrogens, and pesticides from different feed materials and supplementary feeds.
Authors: Kwaß L M, Khiaosa-Ard R, Zebeli Q, Sulyok M, Milojevic V, Metzler-Zebeli B U
Journal: Journal of equine veterinary science
Summary
European researchers used liquid chromatography-tandem mass spectrometry to analyse 108 feed samples across multiple product categories—hay, processed roughage, grains, and supplements—sourced from different countries to quantify exposure to mycotoxins, phytoestrogens, pesticides, and veterinary drug residues. Nearly all samples contained multiple fungal metabolites, with Fusarium toxins predominating, whilst processed roughage products (particularly lucerne-based cobs, cubes and pellets) showed substantially higher phytoestrogen concentrations than hay. Supplementary feeds, especially grain-based mueslis and mashes, emerged as the primary sources of pesticide and veterinary drug contamination, with unexpected contaminants including colchicine and monensin detected in 10–20% of samples, though risk assessment suggested these posed no acute threat at current exposure levels. For equine professionals sourcing feeds, these findings highlight the variable contamination profiles across product types and the importance of supplier transparency regarding mycotoxin screening, particularly for processed roughage and concentrates. The data support calls for harmonised testing protocols and regulatory frameworks to mitigate long-term health impacts, especially given the omnipresence of fungal metabolites and the potential for cumulative exposure across multiple feed components within a ration.
Read the full abstract on PubMed
Practical Takeaways
- •Source feed materials carefully: processed roughage products pose higher contamination risks than traditional hay, particularly regarding phytoestrogens
- •Scrutinize supplementary feeds and grain-based supplements for pesticide and drug residues; request supplier testing data and certificates of analysis
- •Advocate for routine feed testing protocols in your operation and educate clients about contamination risks; push suppliers for transparency on quality control measures
Key Findings
- •Nearly all 108 feed samples contained multiple fungal metabolites with Fusarium toxins being most prevalent across European markets
- •Processed roughage products (cobs, cubes, flakes, pellets) containing lucerne showed significantly higher phytoestrogen and plant toxin concentrations compared to hay
- •Supplementary feeds, particularly grain-based mueslis and mashes, were more prevalent sources of pesticide and veterinary drug residues than base feed materials
- •Colchicine and monensin (both highly toxic to horses) were detected in 10-20% of samples, though risk assessment indicated no acute health risk at detected levels