Moo Moo Farm, is, well, Moo Moo Farm, where Moo Moos graze along the plains around the track. This course is very easy to race across, since it has wide lanes and smooth turns The only obstacles are the Monty Moles that pop out of holes that jettison a racer upon collision and the support beams holding the bridge across the farm at the end of the track. Hitting one too hard will make a racer lose control.
In Grand Prix mode, you can cut off a few seconds from your lap times by hugging the right side of the course. This is especially useful at the end of the course (right before the starting line) as you go under the bridge (shown below).
