The 13 Herens cows broke through their pen and through several lines of security around their pasture before running toward a cliff and either falling or throwing themselves off of the 50metre drop near Levron in Valais on Wednesday.
Twelve of the cows died in the fall, while the 13th survived. The surviving cow, which likely landed on the others at the bottom of the cliff, was injured and taken to an animal hospital in Bern.
In total, the cows were believed to be worth around 20,000 francs (£16,000).
The couple who own the land said the cows may have been chased by a predator before falling or leaping off the cliff.
‘The cows broke through several lines around the pasture before finding themselves on the ridge. They fell into the void, as though they were forced into it,’ Norbert Terrettaz, president of an farming insurance company in the region, told La Nouvelliste.
Terrettaz said that that the behavior was unusual, as cows ‘have a tendency to disperse’ when faced with danger instead of following one another ‘like sheep’.
He said a predator on the land could have been a dog off the leash or a wolf.
The cows did, however, have to pass through a pasture occupied by four yaks before reaching the cliff.