Andrew Marshall said there was a ‘high risk’ of attack as the breed of cows which rounded on Mike Porter were ‘unpredictable’, ‘more excitable’ and ‘less calm’.
When threatened, the cows - a continental breed - trigger a ‘fight or flight’ response, and in the worst possible scenario they seek to ‘eliminate’ threats, he said.
Mr Porter was walking with his brother John and his two dogs when they were encircled by the ‘highly excited, jostling’ herd half way across a field in Turleigh, Wilts.
The 66-year-old, like his brother, was knocked to the ground on the public footpath when the herd got on their hind legs and stamped down on the elderly pair with their front legs.
Mr Porter, who had just retired from his post at Edinburgh University, managed to scramble out of the field but collapsed and died shortly afterwards. A hoof mark was found on his chest.
The attack happened on Timothy Rise Farm on May 13 2013 in an area where three previous cow attacks had injured members of the public, Salisbury Coroner’s Court, Wilts, heard.
Today, Mr Marshall - an independent agricultural expert since 1985 who has previously consulted for the government - said it was possible the same herd could have carried out each attack as records showed 31 cows on the farm were also there at the time of previous attacks.
He also told jurors farmer Brian Godwin and his family farmed beef cattle and raised them as ‘suckler cattle’ - where the livestock wean their own calves and have little human interaction.
Mr Marshall, who visited the farm himself with HSE inspectors and police, said: “A farmer who puts suckler cows in a field with a footpath is aware there is a high risk of attack to the public.
“Farmers are very careful. As soon as you got suckler cows on a farm you have to be very careful.
“There were 31 animals that were in the area of where the incident occurred that were also on the farm for all three incidents.
“If those animals had been involved in previous incidents then these animals are not frightened of humans and if they perceive them entering their comfort zone they are confident enough in dealing with it.
“Previously the cattle attacked but then left the individual as they had dealt with it. But in this instance they pursued the Porter brothers as they left the field.
“This time they were going to deal with this threat and they had to be eliminated.
“Cows are like teenagers and they push the boundaries. If they get away with something they will keep pushing that boundary.
“But we don’t know if they are the same cows but they will remember previous circumstances. If they come together there is a large potential risk.”
Mr Marshall said the cows bred on the farm were continental cows - notably limousin or simmental cattle - weighing in excess of three quarters of a tonne each.
He said: “You have continental and British breeds. Continental cattle are larger animals and tend to be unpredictable, more excitable and less calm in their attitudes.”
He added farmers should be aware of all previous incidents when weighing up the risk to public.
However, the inspector from the Health and Safety Executive said their records only had one reported attack as the others went unreported.
Dawn Lawrence said she was only aware of the injuries sustained by David Billington in October 2011 and they wrote to the farm about the need for additional safety measures.
The minimum safety measure was carried out by the Godwins, which was signs installed on the stiles saying: “Cows and calves in field.”
Of the signs, she said: “They don’t actually prevent risk. They just give information.”
However, she added the duty on the farmer isn’t to prevent risk, but to reduce the chance of such a risk happening.
In addition, HSE records showed a member of the public had complained separately to them in 2008 about the way the cattle behaved when being moved, but it caused no injuries and was not one of the previous attacks talked about at the inquest.
Mike Porter, from Edinburgh, was visiting his brother John, 72, in Bath and they had taken his dogs for a walk by the Avon Canal.
They had climbed over a ‘kissing gate’ before walking on a public footpath which ran diagonally across the centre of the field. across a footpath.
John was hospitalised with injuries in the unprovoked attack as he and Mike Porter managed to escape the herd in separate directions, the inquest heard.
John Porter, now 74 who worked in agriculture and on farms all his life, said: “I cannot say which cows or what cow was attacking us but they seemed to deliberately trample on you. It was extraordinary.
“It seemed to be something they really wanted to do.
“All of a sudden they dispersed and we picked ourselves up and walked out the field, thinking we are battered and bruised but we are ok.”
He added: “We just wanted to get out.”
Wessex Water van driver John Wall, 38, saw the cows attack and said: “They did nothing to antagonise the cows. The cows were going mad.”
Mr Porter died at the scene and a post mortem revealed he had fractured ribs and visible injuries to his limbs, chest and abdomen.
Evidence of a hoofmark was found on his chest and he died from internal bleeding.
Jurors heard yesterday how Simon Dark was attacked by cows in the same ‘Elbow Field’ in April 2008. while Mr Billington, 50, and Brenda Wall also told of cow attacks on them in the neighbouring field in 2011, which is part of the same farm.
After treatment from emergency services, Mr Dark added in his statement that the farm owner shouted to them: “There’s nothing wrong with my cows.”
Farmer Brian Godwin, 81, who rents the land from Turleigh Manor, admitted the farm had suffered from previous cow attacks.
He said: “We had problems before but we had done everything that we thought we needed to.”
When asked why he had not taken further safety measures, he added: “Some of the recommendations were adopted but we didn’t think an incident like this would happen.
“I never anticipated it whatsoever.”
He said that if a particular cow was known to be aggressive, it would be slaughtered.
The inquest continues.