A blond city girl named Amy marries a Wisconsin farmer.
One morning, on his way out to check on the cows, the farmer says to her, "The artificial insemination man is coming over to impregnate one of our cows today. I drove a nail into the 2 x 4 just above the cow's stall in the barn. Please show him where the cow is when he gets here, okay?"
The farmer leaves for the fields. After a while, the artificial insemination man arrives and knocks on the front door. Amy takes him down to the barn. They walk along the row of cows and when Amy sees the nail, she tells him, "This is the one right here."
The man, assuming he is dealing with an airhead blond, asks, "Tell me lady, cause I'm dying to know. How would you know this is the right cow to be bred?"
"That's simple," she said. "By the nail that's over its stall," she explains very confidently.
Laughing rudely at her, the man says, "And what, pray tell, is the nail for?"
Amy turns to walk away and says sweetly over her shoulder...."I guess it's to hang your pants on."