Foxtail-induced ulcerative stomatitis outbreak in a Missouri stable.

This research paper examines an incident where 20 out of 25 horses in a boarding stable in Missouri suffered from gum inflammation due to ingestion of hay infested with foxtail seed heads. The issue was resolved once the hay source was changed.

Incident Overview

• The incident took place in a boarding stable in Missouri that housed 25 horses.
• 20 of these horses were diagnosed with gingivitis/stomatitis, which is inflammation of the gums and mouth.
• Upon physical examination, the affected horses showed varying levels of gum inflammation – some had mild swelling and others had more pronounced swelling, redness, sores and bleeding in the gums.
• Fine hair-like material was discovered embedded in the areas severely affected by the inflammation.

Investigation and Findings

• Biopsies of the affected gum tissue from 4 horses were taken for investigation.
• These tissue samples showed high levels of inflammation with pus and, in some cases, a large number of eosinophils, which are a type of white blood cell.
• Grass awns, or seed heads, were discovered in the tissue samples, both in cross and longitudinal sections.
• The same type of seed heads were found in samples of the hay that the horses were being fed.

Link to the Hay Fed to the Horses

• From the stable’s records, it was found that all the affected horses had been fed the same hay suspected of causing the inflammation, except one.
• However, this horse had access to the suspect hay while exercising in the paddock.

Resolution and Conclusion

• The mouth inflammation in the horses became better after the stable started sourcing hay from a different place, reinforcing the link between the inflammation and the hay from the previous source.

Overall, this case study serves as a reminder of the potential health risks posed by certain types of seed heads in hay, specifically foxtail seed heads, to horses and the need for careful sourcing and inspection of hay.