Here are two documents that will come in handy as you play...
The Great Cow Race Manual
(this is a PDF file)
The Great Cow Race official walkthrough
written by game designers Heather Logas and Dave Grossman!
If you're stuck and prefer to use walkthroughs only as a last resort, don't forget that the game has an in-game hint system, too. Just click the ? button in the lower right corner to get a hint.