Video report by David Hirst
A North Yorkshire woman, who was left with life-changing injuries after being trampled by cows, says the ordeal was "terrifying".
Janicke Tvedt, 55, was targeted by a herd of cows when she was out walking her dog with her partner in Masham in July.
The attack destroyed her colon, leaving her needing a colostomy bag. She also suffered seven broken ribs and has hoof-shaped scars on her body.
Ms Tvedt said she was walking with her dog when she saw a group of around 30 cows over a hill in the distance, so she walked around them to give them a wide berth. But one of them charged at her dog.
She said: "We were a bit shocked. We were about 30m from the stile that gets you out of the field so made a beeline for that. Three more cows came back though and trapped us against a hedge. They were massive and there was nowhere we could go.
"I was standing there trying to be really calm thinking they were just going to sniff us for a bit then leave us alone.
"After 10 minutes one of them headbutted me in the knee while trying to go for my dog.
"This black cow reared itself up and stamped down with its two front legs on to my abdomen. It must have done that three or four times. I've got the hoof marks still.
"Another cow started having a tussle with it and was knocked over and rolled over my body and crushed me.
"Eventually I just laid there unable to move and they went away."
Why do cows attack people?
According to The Ramblers Association, cattle will instinctively become more aggressive when protecting calves - particularly during spring when cattle are rearing their young.
In order to keep yourself safe, they recommend avoiding getting between cows and their calves, moving quickly and quietly around the herd, and closing gates behind you. If you have a dog, keep it on a short lead.
Ms Tvedt and her partner ended up climbing a tree to get away from the cows. Later an Air Ambulance landed and took her to hospital for treatment.
She said: "It was terrifying but it all seemed to happen in slow motion. I can remember every single second of it."
Ms Tvedt is now warning other dog owners that cows are dangerous and wants more signs in fields to alert dog walkers to their presence.