"Right" said the dairy farmer to his wife who was a dizzy blonde, "The insemination man is coming over to impregnate one of our cows
this morning, I have to go out, I drove a nail into the rail above the cow's stall in the barn so you know which cow it is."
"O.K." She said. "The man arrives. "You must be the insemination man" she says, she takes him down to the barn and they walk along
the row of cows. "This is the one" she says. The man is terribly impressed." And can you tell me what's the nail for?" he said.
She turns and walks away and with complete confidence, says over her shoulder....."I assume it's to hang your trousers on."