https://phaidra.vetmeduni.ac.at/o:4898 Exposure of horses to biotoxins, phytoestrogens, and pesticides from different feed materials and supplementary feeds Khiaosa-Ard, Ratchaneewan Ratchaneewan Khiaosa-Ard 0000-0003-3359-5787 University of Veterinary Medicine Vienna Kwass, L. M. L. M. Kwass Zebeli, Qendrim Qendrim Zebeli 0000-0001-5188-9004 University of Veterinary Medicine Vienna Sulyok, M. M. Sulyok Milojevic, V. V. Milojevic Metzler-Zebeli, Barbara Barbara Metzler-Zebeli 0000-0002-2413-4957 University of Veterinary Medicine Vienna Elsevier journal article open access eng Background The occurrence of biotoxins and chemical residues in marketed horse feeds has direct influences on horse health but has not been studied yet. Aims/objectives The study investigated the exposure and health implications of contaminants in various horse feedstuffs available on the European market. Methods A total of 108 feed samples representing diverse product categories such as hay, processed roughage products, grains, and various supplementary feeds were collected from different European countries and analyzed for contaminants, including mycotoxins, phytoestrogens, pesticides, and veterinary drug residues using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results Findings revealed that nearly all samples contained multiple fungal metabolites, with Fusarium toxins being the most prevalent. Processed roughage products (e.g., cobs, cubes, flakes and pellets) containing lucerne exhibited high concentrations of phytoestrogens and plant toxins compared to hay. The data also showed that supplementary feeds, particularly grain-based mueslis and mashes, were more prevalent sources of pesticide and veterinary drug residues than feed materials. Unusual substances in horse feed like colchicine and monensin, both highly toxic to horses, were also detected in roughly 10 to 20 % of the samples. However, our risk assesement suggests that the contamination of both compounds would not pose an acute health risk to horses. Conclusions The study reveals the complexity of biotoxins and chemical residues and their potential risks in marketed equine feeds and underscores the critical need for targeted regulations, routine testing to ensure equine health and welfare. Ergot Alkaloids Horse Feeding Horse Health Mycotoxins Veterinary Drug Resistance http://creativecommons.org/licenses/by/4.0/ https://phaidra.vetmeduni.ac.at/api/object/o:4898/download 10.1016/j.jevs.2025.105632 https://phaidra.vetmeduni.ac.at/o:605 application/pdf Journal of Equine Veterinary Science issn:1542-7412 VoR Journal of Equine Veterinary Science 151 707.77 kB 2025