An Australian farmer has found six cows lying dead in a row, in what experts have attributed to a lightning strike.

The animals were discovered next to a barbed-wire fence on a paddock in Queensland last week, a few days after a heavy storm.

The cows' owner, Derek Shirley, said he was "stunned" by the find.

Dr Sabrina Lomax, a livestock expert from Sydney University, said she believed all six animals had been touching the fence when they died.

"In these sort of freak accidents, it was just an inconvenient placement of the animals in regards to the [lightning] strike," said Dr Lomax, an animal behaviour and welfare researcher.

"They would have died instantly from a massive heart attack."

Mr Shirley, whose farm is about 70km (40 miles) south of Brisbane, said he initially thought the cows had been poisoned.

"You just do not see them all lined up against the fence," Mr Shirley said.

"You could nearly run a ruler on them."

Science commentator Dr Karl Kruszelnicki said the cows may have been shocked when the lightning hit the ground.

"The electric field goes in through their back legs, through the body… and they have a heart attack," he told the Australian Broadcasting Corp.

In 2016, more than 300 reindeer were killed in a lightning storm in Norway.