Here's a passage about how cows inform on witches:
For sometimes when a cow has been injured in this way, and they wish to discover who has bewitched it, they drive it out into the fields with a man's trousers, or some unclean thing, upon its head or back. And this they do chiefly on Feast Days and Holy Days, and possibly with some sort of invocation of the devil; and they beat the cow with a stick and drive it away. Then the cow runs straight to the house of the witch, and beats vehemently upon the door with its horns, lowing loudly all the while; and the devil causes the cow to go on doing this until it is pacified by some other witchcraft.
A frightening image, the cow battering the door with its horns. And god save you if it was your door the cow chose.