"It sent me flying backwards. It all happened so fast that I don't know exactly what happened."
Mr Walters said even though they were both in shock he had Mrs Walters in his vehicle and on the way to the hospital within 60 seconds.
"Because of my vehicle being right there at the scene I had her there very quickly and safely."
Mr Walters said the 17-hour surgery performed by Hutt Hospital surgeon Dr Annie Fullarton was "just incredible".
"One of the surgeons said they have never seen an injury so bad. It was crushed, smashed, and just degloved basically."
His wife said she was "very impressed" with the surgery.
"I had this idea that I would be getting a plastic hand or something," she said. "It's just a silly idea that you get in your head."
Mr Walters said they were "the most careful people you will ever meet with many, many years experience around horses".
The horse had been on a float before and had gone through an "extensive float programme" which included training them to walk on structures via a large sheet of plywood.
For now Mrs Walters was staying at her sister's house close to Wellington Hospital with her mother looking after her.
She is slowly beginning to move her fingertips and is scheduled to have more surgery to remove pins in her fingers on February 2.
Mr Walters said he was grateful for all the support he had received from friends.
"It's a comforting feeling to have such caring people around us.
"It's important to note that the accident happened but it's the support that's not often written about."