If you had three horses react, I'd bet too that it was the vaccine. I've had enough problems with Ft Dodge that I avoid it whenever possible. Generally though, I only have one or two mares who routinely react to almost any vaccine. It's a mother & daughter, and they now get oral banamine along with vaccines. The daughter had an abscess years ago from a vaccine (given by a vet) and just seems super sensitive.
Jan
Jan