Foxtail - When Is It a Problem????

Sold some hay to a customer today, they were replacing a second cutting they got from someone else - that was full of foxtail. One of their horses had some mouth damage and a vet was called in to treat the horse.

I don't recall seeing much, if any foxtail when we made our first and only cut of Timothy, but later in the summer, found a bit here and there.

Help me understand - is it the seed of foxtail that causes the problems, or is it the structure of the head itself that causes damage?

Reason I ask is - if it is the seed only that causes damage, a first cut might contain some foxtail, but harmless as it hasn't gone to seed - unless the physical structure of the head is the root cause of issues?

The buyer showed me picks of the foxtail in her hay had they were loaded with seeds.

Only one of their horses had a problem. The customer also said she was told only certain types of foxtail were to be avoided - never heard that before.

Any info is much appreciated.

Thanks,
Bill

Foxtail - When Is It a Problem????