"I also want to tell motorists, Joe and I don't own the cattle that were a hazard on the Whananaki North Rd," he told the Advocate this week.
A nephew had put 10 bulls and three heifers on to land which the brothers own in conjunction with their sister, the nephew's mother.
The brothers had provided a couple of hectares to graze the cattle.
"But there wasn't enough feed and the animals broke fences, becoming a nuisance on the road," Joe Cooper said.
Irate motorists had honked and made rude gestures because of the wandering stock.
Mortified by what they saw as unjust criticism, the two veteran farmers were doing their best to shift the cattle to a secure paddock when an 18-month brindle bull with big horns knocked Api Cooper unconscious and appeared ready to gore his inert body.
After the dogs, Fay and Diesel, came to the rescue and the airlift was organised, Hikurangi police Senior Constable Russell Rawiri arrived.
He said members of the public had secured the animals.
The first he had known of cattle causing any traffic problems was when motorists at the scene told him about it, Mr Rawiri said.
"They said one of the bulls had tried to hook a car with its horns.
"But I hadn't received any complaints, except one from Joe [Cooper] ages ago, so the police took no action over these bulls."
Environmental Northland handles stock control for the Whangarei District Council.
Director Keith Thompson said the company had not impounded the animals.