If your main objective is to have your complaint heard by us, and reviewed with your veterinarian, then the NYSVMS complaints process may be a good fit. You can learn more about it by visiting: https://nysvms.knack.com/complaints. Note that NYSVMS can only perform this service if the veterinarian involved is a member of our association.
If you're hoping to have official disciplinary action considered as a consequence of possible malpractice or unprofessional behavior, or if the veterinarian in question is not a member of NYSVMS, you can register a complaint with the NY State Education Department (NYSED). That agency can investigate and impose penalties through its Office of Professional Discipline (OPD), since it’s the licensing body for professionals in New York. If you do choose to register a complaint with them, you'll forfeit any option to use the NYSVMS complaints process. We cannot become involved in situations that are already being handled by government, regulatory or legal agencies.
NYSED's investigations can take some time, but they do get done. See http://www.op.nysed.gov/opd/rasearch.htm for a list of previous enforcement actions, searchable by the veterinarians’ last name.
This page has basic information about investigation and prosecution of professional misconduct in NY State: http://www.op.nysed.gov/opd/. You can get phone and email contact information there.
This is a link to the complaint form instructions: http://www.op.nysed.gov/opd/complain.htm
And this is a link to the complaint form itself: http://www.op.nysed.gov/documents/opd-complaint.pdf