A policeman suffered four broken ribs and a punctured lung when he was attacked by cows.
Inspector Chris Poole was surrounded by 50 half-ton beef cattle, which repeatedly butted and stamped on him.
He was rescued by the Sussex Police helicopter which he ran for six years, and he later survived a second life-threatening ordeal in hospital when one of his broken ribs severed an artery.
Recovering at his home in Brighton last night, Insp Poole said he wanted to warn all walkers to give cows a wide berth.
The 50-year-old officer said: "I worked on a farm and with cattle when I was a youngster and always told people not to worry about cows and said they never attacked. Little did I know."
He was walking his ten-year-old Golden Retriever Zak on the South Downs near Lewes and decided to put him on a lead as they entered the cattle field and continued along a designated footpath.
Insp Poole, who works in the criminal justice unit at Lewes, said: "Suddenly, one cow started mooing and then others began running towards me. There were about 50 of them, some were cows with calves but all were fully grown.
"We were surrounded but I wasn't scared and waved and shooed them away as they came close. They were focused on Zak and became more agitated as they got nearer and nearer.
"Then I felt this cow butt me hard in the back. I fell to the ground and let go of Zak's lead.
"There were hooves all around me and I was being repeatedly head butted as I lay there. I felt my ribs go. One cow stood on my arm and broke my watch, and I suffered a gash on my head."
The cows became distracted when Zak fled and Insp Poole seized the moment to get up, stagger to a gate and escape.
He made his way to a barn where he saw a Land Rover and a man out with his two dogs.
He said: "I sank to my knees, holding my chest. I could barely breathe."
The dog walker and another man and two women, one a former nurse, came to his aid and minutes later the Sussex Police helicopter arrived to take Insp Poole to Eastbourne District General Hospital.
He recognised a PC on board the helicopter.
He said: "He was one I had recruited just before leaving the unit in Shoreham nine years ago. It was ironic I should become a patient of theirs."
Bystanders held on to Zak and Insp Poole managed to telephone his wife, Jill, a 46-year-old author. She joined him in the hospital's accident unit.
Insp Poole was given morphine and treated for four broken ribs. He had a chest drain for his punctured lung and his right arm swelled to twice its normal size. He was bruised from his thigh to his shoulder, but worse was to come.
Three days later, he was leaning forward to speak to a patient next to him when he felt intense pain.
A sliver of bone from a broken rib severed an artery and Insp Poole lost five pints of blood in as many minutes.
Mrs Poole was told it was touch and go as they rushed her husband into theatre. Surgeons had to split his ribs to stitch the torn artery and remove the sliver and an hour later he was in the recovery ward with 45 staple stitches in his side.
Insp Poole remained in intensive care for 24 hours and spent a total of 11 days in hospital. Back home with his wife, their 16-year-old daughter and Zak, Insp Poole said he considered himself lucky.
He said: "I would have died if not for the walkers, the helicopter and the hospital staff.
"I was extremely lucky - but it was unlucky the cows attacked in the first place. It is very rare but obviously it can happen.
"I had never heard of killer cows before but I hope this is a warning to everyone."
Eight people reportedly have been killed by cows in the UK in the past ten years and the RSPCA last night said although attacks were rare, cows will become protective of their young to the point they become aggressive, especially if a large dog is nearby.
The society's Klare Kennett said: "If you walk through a field with cows in then keep as far away from them as possible."
An inquest earlier this year heard how a father of four and retired doctor, 73-year-old Tom Bolton, was killed by stampeding cows near Leighton Buzzard, Bedfordshire.
Have you ever encountered a herd of angry cows? Tell us your experiences below.
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