Here we give our horses a set of shots in the Spring and the Fall. Is this normal for the rest of the world? It just seems over kill to me, but I go to shows and it is safer for everyone to keep those shots current.

Anytime you are moving from one place to another or are interacting with large groups of animals you normally need to inoculate more often. You never know where the other animals have been or what diseases are prevalent where they are. Think of how often you worm your horses. Because horses don't live in a nice house with carpet they are more likely to come into contact with diseases and parasites, and the best way to stop this is to use preventative measures.

I am really torn on the shots for the animals. They really do seem like overkill, even for animals who are showing a lot. Horses become hypersensitized to the tetanus vaccine, that's how the immuno globulin shot for humans is made.

Regarding the OP yes that is normal. Most shots are only needed annually but are recommended twice a year for at risk horses. If the shot worked in the first place it wouldn't be needed more often, except then they wouldn't sell so much.

One thing that I do when traveling is take my owner water and buckets. At a show I never allow my horse drink from the community water trough. I have been told that many problems are transfered by the horse drinking bad water. Plus my horses are used to drinking that water I have at my house.

I think that taking your own water and reducing exposure in that way is an excellent thing. I do not show my horse so we are not in this situation, but if I were I think I would now follow this advice.

I have a question tied in with this. I know some people that do not give their children vaccinations due to religious reasons, are there some horse owners that do the same (not per say for that reason, but do they skip certain shots if they feel they are not needed)?

There is a large debate about vaccinations for both pets and people. Some shots are required by law for domestic animals before you can license them or you can be fined, etc. This is decided upon the threat of an outbreak of a disease that is still active. Depending on where you are however, your animal might not ever have a chance of getting certain diseases based on its exposure to other animals and the diseases ability to be spread between species.

One of the big problems with vaccines is that they are not a 100% guarantee that you will not still contract a disease. You can be up to date on all your shots and still get the disease, and in some cases get the disease from the vaccine. This depends on your immune system, antibody levels for a particular disease, and what type of vaccine it is. Many states in the US allow children to not be vaccinated for religious, philosophical, and medical reasons before entering kindergarten. You can get titers done instead, which check the blood for the level of antibodies for a particular disease. Nothing is foolproof, but by talking to your vet and asking questions you can decide for yourself if and what vaccines are necessary and the possible consequences from your decision.

So does that mean that if you get your horse vaccinated, then it does still get the disease going around, then you are not held responsible if it spreads? I'm trying to find the reasoning behind this myself.

Indeed, you would not be held responsible for a disease spreading because your horse contracted it. It is not your fault that the shot failed.

Regarding human exemptions; you do not need to submit titre tests if there is a religious exemption in place. The exemption is all that is needed.