A veteranarian calls on a farmer. He says, "So what's the problem with your cow?"
The farmer says, "Come look. This is one of my best milk cows, and she went cross-eyed overnight. She's walking into fence posts, she's falling down, and she may break a leg at this rate."
The vet looks at the cow and says, "She's cross-eyed, all right. I've seen this before. I think I can fix it." He goes to his car and comes back with a short piece of garden hose. He says to the farmer, "You stand by her head and tell me if her eyes uncross." He sticks one end of the hose in the cow's ass, takes a deep breath, and blows into the end of the hose. The cow's eyes bulge way out and straighten.
The farmer yells, "You fixed her!"
The vet says, "That usually works. That'll be $150 for my visit."
A week later the farmer goes out to the field and finds the cow has gone cross-eyed again. He says, "I'll be damned if I'm paying another $150."
He goes to the barn, cuts a length of garden hose, and spots his farmhand asleep on a hay bale. He kicks the man's foot and says, "Come on with me." They go out to the cow and the farmer says, "You hold her head and tell me if her eyes uncross."
He gets behind the cow, sticks the hose up her ass, and blows. The farmhand says, "They're still crossed."
He takes a deeper breath and blows. The farmhand says, "Still crossed."
The farmer says, "You're younger than me. Let's trade places. You come back here and blow." They switch places. As the farmer watches, his farmhand pulls the hose out, turns it around, and sticks it back in. The farmer says, "What did you do that for?"
The farmhand says, "Well, hell! You didn't expect me to put my mouth where yours has just been, did ya?"