A 66-year-old woman was trampled to death as she walked her dog in a field of cows and calves in Warwickshire.
Lorraine Richards was a widowed mother-of-three
Lorraine Richards was on land to which the public have access, near Carylon Road Industrial Estate in Atherstone, early on Saturday morning.
Police say she was knocked over and then trampled. Some of the animals in the field were pregnant.
Mrs Richards, from Bretts Hall Estate, Ansley Common, Nuneaton, was taken to hospital where she died soon after.
A police spokeswoman said the widowed mother-of-three's death was being treated as a tragic accident and that police were working with the coroner's office.
A post-mortem examination is due to be carried out on Wednesday.
The dog was not injured.
Richard Sibley, former president of the British Cattle Veterinary Association, told BBC News that such a death was a rare but not unprecedented occurrence.
"It usually happens when somebody's with a dog.
"When cows have calves at foot they're very, very protective.
"If they see anything as a threat to their young they will go for it.
"Cows are normally docile subordinate animals, but their instincts to protect their young will overcome that."
Mr Sibley added: "It's really not wise to be walking in a field of cows with calves with a dog.
"It sounds perverse, but if the woman had her dog on a lead that could be even more dangerous."
He explained that the cows would usually see the dog as the threat and, if it ran off, they would be less likely to attack its owner.
A National Farmers' Union spokesman said people were always advised to follow the Countryside Code.
It states: "Wild animals and farm animals can behave unpredictably if you get too close, especially if they're with their young - so give them plenty of space."
In a statement issued through police, Mrs Richards' family said she regularly walked the countryside, often with the family dog, adding: "(We) are devastated by her tragic and sudden loss and she will be so sadly missed by all whose lives she touched."
Health and Safety Executive figures for the 10-year period to 2004 showed that there were 489 deaths in the agriculture sector - of these, 58 were members of the public.
Livestock-related fatalities were the fifth main cause of death.