What state and what type of job? You don't have a visa?
National Board of Veterinary Medical Examiners
http://www.nbvme.org/?id=12 Exact requirements and licensing would, I assume, vary by state.
Go to the school from which you graduated and ask them if they have info on working in other countries. U.S. Embassy there may have a "Study USA" office. You could also contact schools of veterinary medicine in the U.S. (University of California at Davis is one I know but there are others). Some jobs you're interested in may not require degrees. You may want to talk to corporations in the field (e.g., vet pharmaceuticals).
But, of course, getting a job offer and a visa to work in the U.S. if your big hurdle. May want to get an appointment at the embassy (or walk with an immigration lawyer). Thought of also looking into the same process for Canada, Australia, New Zealand, etc?