Farmers in Devon and Cornwall have been reminded of the dangers to humans and animals from overhead power lines.
The cattle were grazing in a field during a storm
The warning was made by the Energy Networks Association, which is funded by the electricity and gas transmission and distribution companies.
The association said five people on farms are killed each year when machinery hits overhead power lines.
Four cows and a bull died on a Cornish farm last month when cables came down during a storm.
They were electrocuted in a field where they were grazing on the Lizard peninsula.
The association said power lines, which are essential to the UK's power grid, are built mainly through fields to avoid contact with the public.
But it said it means farmers are particularly susceptible to the risk of machinery hitting lines.
It warned that touching a 230 volt line can be fatal and even the lowest voltage lines can produce 10,000 times the amount of current needed to kill a person.