The Nail

A blonde city girl named Amy marries a Colorado rancher.
One morning, on his way out to check on the cows, the rancher says to Amy,
"'The insemination man is coming over to impregnate one of our cows  today.
so I drove a nail into the 2 by 4 just above where the cow's stall is in
the barn.
Please show him where the cow is when he gets here, OK?

The rancher 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 air head blond, asks, "Tell me
lady, 'cause I'm dying to know; how would YOU know that 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?"
The blond turns to walk away and says sweetly over her shoulder, "I guess
it's to hang your pants on."