my goat has a lump on her stomach?

It sounds like an abscess. Most abscesses are harmless and are caused by a bug bite, sting, or a sliver. A small percentage of abscesses on goats are caused by CL. CL stands for "caseous lymphadenitis" and basically means contagious abscesses. It is the pus in the abscess that is contagious to other goats. The bacteria that causes the disease can live for years in the ground or on surfaces such as wood.

Eventually the hair will fall off the abscess and it will open and drain.

To find out for sure whether or not it is contagious you would have to have the abscess lanced by a vet and a sample of the pus sent to a lab for testing.

You definitely can't take a goat with an active abscess to the fair. If it *does* happen to be CL, it could be passed to other goats at the fair if the abscess opens up.

Most likely you will have to have health papers to go to the fair also, and no responsible vet would sign health papers for a goat with an abscess because of the possibility of CL.

If the fair is a ways off, there is a good chance that the abscess will be drained and healed before the fair anyway.

Again, it is most likely a bug bite or sliver, but the only way to know for sure is to have it tested. Since this is a fair goat, the most responsible thing to do would be to have a vet take a look at it so you can be certain you don't take CL to the fairgrounds.