Feed-induced hypersalivation in horses from Austria, Germany and Switzerland.
Authors: Böswald Linda Franziska, Gottschalk Christoph, Kaltner Florian, Merk Joana, Schwaiger Karin, Kienzle Ellen
Journal: Equine veterinary journal
Summary
# Feed-induced Hypersalivation in European Horses: An Emerging Mycotoxin Problem Between 2016 and 2018, veterinarians and horse owners across Austria, Germany and Switzerland reported multiple outbreaks of hypersalivation—a condition previously documented mainly in South America—prompting investigation of potentially contaminated feedstuffs. Researchers analysed hay, forage and pasture samples from 11 case outbreaks where infectious disease and systemic causes had been excluded, employing gross examination, microscopic analysis and mycological culturing with mycotoxin testing to identify causative agents. Two distinct presentations emerged with different aetiologies: ergot sclerotia and ergot alkaloids (particularly ergocornin and ergocorninin) in hay and pasture plants produced foamy salivation with mucosal lesions of the tongue and gingiva, whilst Rhizoctonia spp. fungal contamination triggered serous hypersalivation with substantial fluid loss, likely mediated through swainsonine production. Clinical resolution required days to weeks following dietary change, with recovery timeframes dependent on toxin type, duration and quantity of exposure. Given the emerging nature of this problem in Central Europe and the significant welfare implications—including mucosal damage and severe dehydration—practitioners should maintain heightened vigilance for hypersalivation cases and consider mycotoxin contamination as a primary differential diagnosis, particularly when investigating hay and forage quality during outbreak investigations.
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Practical Takeaways
- •When investigating unexplained hypersalivation in horses, suspect contaminated forage and submit hay/pasture samples for mycological and mycotoxin analysis before assuming infectious disease.
- •Ergot contamination causes foamy saliva and mouth lesions; Rhizoctonia contamination causes severe fluid loss—identifying the fungal source guides management decisions.
- •Feed change alone resolves clinical signs; monitor forage quality carefully during production, storage, and hay making to prevent mycotoxin accumulation in your herd's feed supply.
Key Findings
- •Eleven case outbreaks of hypersalivation in horses from Austria, Germany, and Switzerland between 2016–2018 were associated with mycotoxin-contaminated forage.
- •Foamy hypersalivation with tongue/gingival lesions was associated with ergot sclerotia and ergot alkaloids (ergocornin and ergocorninin) in hay and pasture.
- •Serous hypersalivation with massive fluid loss was associated with Rhizoctonia spp. fungus producing swainsonine.
- •Clinical signs resolved within days to weeks after diet change, depending on duration and amount of toxin exposure.