Sorry - I know this is an old topic, but health certificates are an important topic that can be difficult to understand. I thought I'd post some info on where to find out about requirements about these.
Health certificates are generally required for movement of animals across State lines - however, the rules are different for each state and each species of animal. USDA APHIS has tried to compile all the rules here:http://www.aphis.usda.gov/import_export ... ates.shtml
however, they occasionally change. The safest bet is to have a veterinarian examine ANY animal you plan to take across state lines, and have them check with the state veterinarian's office to find out exactly what you need to transport.
The exam should take place not much before a week before leaving, since health certificates have a time limit on them (which makes sense, since the certificate says the animal was healthy at the time of exam).
Most vets will charge a fee for issuing a health certificate, since the forms themselves aren't cheap. Also, to legally write a health certificate, the vet needs to be both licensed and USDA accredited in the state. For example, right now I'm licensed in Florida, but only accredited in Michigan. Since I'm not accredited in Florida, and not licensed in Michigan, I can't write health certificates in either place now. So make sure you check with your vet about their accreditation status before you plan on getting the health certificate.
Many people just ignore this requirement - while you might be able to get away with it, you may also be liable for a lot of damages if an animal ends up with a disease that's regulated and transmits it to other animals or people. I know of a case where several goats ended up being put to sleep after their owners moved them across state lines without a health certificate, and they tested positive for TB (but ended up not having the disease). It's much safer to follow the rules!