"We walked in and the dog just glided up beside Shortie, clamped down on him and just shook him," she said.
"His mouth was ginormous and when he shook him, the puncture marks turned in to great big holes."
The dog was pulled off Shortie and Doody and her husband Jim rushed their pet to the vet.
Shortie's heart stopped twice and his bowel was hanging outside his body. He had bruised and punctured organs, and muscles split in half.
Doody was upset but did not want to report the dog to authorities because she felt partly responsible.
She said all dog owners needed to be aware but owners of big dogs needed special education. "If you are going to own a big dog like that there needs to be ongoing training."
Doody said Shortie was improving but needed ongoing care, further surgery and was fighting an infection.
Manukau vet Dr Mary-Ruth Doole said the practice saw several animals every week that had been attacked by dogs. "It is a huge problem but it is usually the owner's fault. Dogs are a prey animal and should never be out without a lead."