Mother-in-law

A small farm boy was milking his cow when all of a sudden a bull came
charging towards him. As horrified workers nearby watched, the boy calmly
continued his milking.

To everyone´s astonishment, the bull stopped a few inches from the boy,
turned around and walked away .

"Weren´t you afraid?" one of the workers
asked the boy.

"Not at all,"the boy replied , "I knew this cow was his mother-in-law."