This is actually very old news. I was taught this as a child.
Cows also make excellent barometers. Most animals are affected by barometric pressure and an ensuing storm. Ever drive past a pasture on a seemingly clear day and see all the cows laying down??
Drop in barometric pressure affects the eating habits of most. My grandfather taught me that using the cow test to see if it was worth it to go fishing. If the cows are laying donw dont bother to go fishing, they wont be biting.