Constipated Horse

Farmer John goes to the vet and says, "My horse is constipated."

The vet says, "Take one of these pills, put it in a long tube, stick the other end in the horse's ass, and blow the pill up there."

Farmer John comes back the next day, and he looks very sick.

The vet says, "What happened?"

Farmer John says, "The horse blew first."