molded hay

Question
I think my daughters 2 yr old QH, ate some molded hay. The only thing that is happening that makes me wonder is he coughs after he has been working out awhile. He is eating fine and his messes in his stall are normal. Do I need to call in a vet or could the coughing be something else? We work him out in an indoor facility when it is raining and on occasion it can get dusty. Help me please, if he is at any risk of serious illness I need to know what to do.

Answer
Hi Stephanie,

It is possible that the horse is coughing because of the moldy hay...but it is doubtful if the condition will last if the bad hay was a one time thing.  A chronic cough from the heaves or COPD is generated from a long term exposure to mold/dust and poor air quality and takes several years to develop (unusual to find horses with the heaves under the age of 5).  If the horse was to colic from the mold it encountered it would happen within hours of having eaten the hay.  If it does colic...by all means you should call the vet.

Where there is mold there are mycotoxins (metabolites of fungus)and these too can cause health issues, but generally only with either high or long term exposure...so I wouldn't worry about them if you get the mold issue under control quickly.

The arena dust could certainly contribute to an irritating cough, especially if manure was ever used to increase moisture holding of the footing (or if manure is not controlled in the arena).

It also could be a cough due to an airborne allergen.  I manage a University horse barn where we get 65 new horses in each fall from various locations.  Horses that are sensitive to airborne allergens have flare ups about 7-10 days after they arrive, often times from exposure to new weeds.  This is further irritated by any dust that they may encounter in the indoor or outdoor arena.  They generally readjust over time, and return to their original state of sensitivity.

If the cough persists, especially given the horse's age, I would call the vet for a routine call.  He should probably be checked for allergies or an upper respiratory condition.

Hope this helps,
Thanks, Corlena