"Parts of his body are badly swollen and the dog has taken a few bites out of him."
The dog grabbed the horse by its throat, but missed the windpipe, Toni said.
She said fortunately his prospects are good, despite the ordeal.
"The vet believes Tomahawk Rebel will make full recovery."
Toni said she is shocked that what happened to her horse is even possible. She has notified police and the SPCA about the attack.
• If you have information about this attack or the dog involved please contact Horowhenua District Council's customer services at 366 0999. They are aware of this incident and the council said it had been in contact with Toni.