Some first year ISU veterinary students are with one of their instructors at a remote Nebraska sheep farm. One of the students asks the instructor, "I'm so horny. What do you do when you're this far from home and you need to get laid?" The instructor says, "Well, typically when that happens, we tell our students to use one of the sheep." The student thinks it must be a joke, but he's so horny he doesn't care and grabs one of the sheep and heads off behind the bushes. When he gets back, the other students and the instructor are laughing hysterically. The student yells, "I knew that had to be a joke!". The instructor says, "No, it's not that! Of all the sheep you picked the ugliest one!"