Firefighters from Strood were called to the Wainscott bypass yesterday afternoon after a horse box toppled over.
It happened just after 1pm between the Higham turn off and the Four Elms roundabout.
Crews were joined by the animal rescue unit.
A Kent Fire and Rescue spokesman said: "The horse box was on its side and the horse was obviously quite panicked. It had its legs in the air.
"The fire crews worked on getting inside it first and we went inside and managed to calm the horse down.
"Because of the state of panic the horse was in, there was talks of possibly putting the horse down but we weren't having any of that.
"Once the horse was calm, we dismantled the trailer, allowing the vet access to sedate the animal before it was transferred to a second horse box."
It is believed the horse suffered minor cuts.
The driver of the vehicle was unharmed.
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