"Cross-Eyed Bull" joke

An aging cattle-rancher bought a bull at a livestock auction. When he got it to the ranch house, he noticed that it was cross-eyed. Very upset that he'd received damaged goods, he called a veterinary optometrist to come out and look at his new bull's cross-eyes.
The optometrist checked out the bull's eyes, then proceeded to go to his truck for a 10 foot section of plastic hose and an air compressor. He cranked up the air compressor and hooked the hose to it, then inserted about 2 feet of the other end of the hose into the bull's colon. He then shot a highly charged spray of air into the hose, causing the bull to literally jump off the ground. He then walked around to the front of the bull and said, "Well, that takes care of his cross-eyes. They're normal now." He then handed the rancher a vet bill for $1,000.
The rancher was extremely disturbed by the $1,000 vet bill. He said, "My God, you spent all of 10 minutes with the bull and all you did was blow some air into its ass."
The vet replied, "Yeah, but I had to drive 20 miles to get here, I had the necessary equipment and expertise, and the the bull isn't cross-eyed anymore, so my treatment worked!"
About six months later, the rancher was staring at the bull and noticed that its eyes had crossed again. Extremely disturbed, the rancher thought to himself, "No way am I going to pay that rip-off artist vet $1,000 to come out here again and blow air up the bull's ass.
So, the rancher grabbed an old garden hose and cut off a 10 foot section. He then went to the bull, shoved about 2 feet of the hose into the bull's butt, went to the other end, put it into his mouth and blew air into the hose as hard as he could. The bull acted completely unaffected and when he looked at the bull's eyes, they were still crossed.
The rancher went to one of his healthiest looking hired hands and asked him for help. He told the hired hand, "I guess I'm too old and don't have strong enough lungs to blow enough air into the bull at a high enough pressure."
The hired hand exclaimed, "Don't worry, my lungs can do it."
The rancher said, "I'll go around to the front of the bull and let you know when its eyes go straight."
The rancher heard a commotion and noticed that the hired hand had taken the hose out of the bull's butt and was putting the other end in. The rancher said, "What the hell are you doing?"
The hired hand replied, "Certainly you don't expect me to blow on the same end as you did?"