This happened in a little town near me about a couple of years ago.
Evidently these cattle all milled around a tree when the storm hit, and a bolt of lightning struck the tree.
He lost 50% of his stock in a split second....tragic.

Lightning strike kills Dorrigo cattle
By Steve MacDonald

Friday, 04/11/2005

A staggering 68 dairy cows, all in full milk, have died on a farm near Dorrigo after being struck by lightning on the last day of October.

The cows, all camped in a paddock, were struck by lightning at lunchtime when a fierce electrical storm hit the area at Fernbrook on the Waterfall Way.

Most of those killed were jerseys along with a few holsteins.

Sixty-nine cows on the farm are understood to have survived.

The Marks family has been herd recording and breeding for over 60 years and it is a major loss of bloodlines from the stock, hit by a single strike.