Yes, every state has different laws and procedures governing how to collect for veterinary malpractice.  Most of these laws are similar, but you need to understand that it is the law in your state that will determine whether you win. The way to check on your state law is to go over to a law library and to look for a summary of state law (every state has such a summary) and then look under "animal law". Then you check your specific state's law on the issues that we will discuss here.
 
 

Time limits to file your action are called "statutes of limitation." States differ on the length of these, but it's rare that a state will have a statute of limitations shorter than six months.  So as a general rule, it is always wise to file as quickly as possible.  If your suit is against a public entity such as a county or the animal regulation department, then you may also have to go through a "claims procedure" prior to filing your lawsuit, and the time limitation for such "claims" against public entities is often 
very short.

Usually you sue either because the other side was negligent or because the other side did something intentionally, such as shooting your animal, and this is called an "intentional tort".  In extreme cases you can also win for punitive damages if the defendant was really mean or wanted to hurt you by 
injuring your companion animals, such as in a domestic case where your former partner hurts an animal in order to upset you. The theory on which you are basing liability is called your "cause of action" and sometimes there are several different causes of action (legal theories).

In the case of veterinary malpractice, there is a special standard of competence that the veterinarian has to live up to.  That means the veterinarian has to be as competent as the normal veterinarian practicing in that region of the county.  He or she has to use the same skill in diagnosis and procedures as another competent veterinarian. The hard part in pursuing veterinarian malpractice is finding another vet who is willing to testify that your vet was negligent or incompetent.  You should try, before you even file your case, to find another vet who is willing to to testilfy for you in court. If you cannot find anyone who is willing to do that, then it is unlikely that you win your case. You need experts to win! And you should think twice about filing a suit.  Perhaps the veterinarian is willing to settle the matter, or to drop his/her claim for fees. 

Also, there is often a Board (usually in the state capital) that supervises the practice of veterinary medicine and licenses the veterinarians.   You can complain to that Board, and this is often an effective way to make your views known.

Yes, suits are expensive, time-consuming and you often lose them. So before you file your suit, call your veterinarian or veterinary hospital and try to work out a compromise. They will often be anxious to preserve their reputation and may be willing to talk about a compromise or waiver of their hospital fees. This is especially true if you are a longtime customer.

The sooner you file your case, the more memory your witnesses will have of the incidents that form the basis for your lawsuit.  Because of the memory factor, it is advisable to write down everything that happened as soon as possible and have your witnesses do the same. Make a list of all witnesses 
and their addresses and phone numbers.  If a witness is about to leave town, ask her/him to write down their testimony in a form that is usable in court in your state such as a declaration or an affidavit. Find out what the requirements are in your state for using the testimony of a witness who is no longer available, and make efforts to preserve all evidence such as receipts, invoices, and medical or necropsy reports.

It is usually advisable to file your suit in one of the courts that prohibit lawyers, such as your small claims courts, because the procedures and forms there are a lot easier.  The problem with these informal courts is that they limit the amount of money you can recover.  Find out the "jurisdictional 
limit" in your state for "small claims" filings.

The amount of money that you are suing for is called your "damages". For injury to an animal (or its death) you can always sue for the amount the animal was worth, i.e. "market value". Animals, unfortunately, are considered property and so they are considered to have a market value. You can also sue for any amounts you have directly expended on the animal due to the injury (e.g. veterinarian bills, burial expenses, necropsy expenses).  Often you can also recover for days you took off works, or mileage for trips you were forced to make because of the other side's actions. In some states, but not 
most, you can also sue for emotional pain you suffered because of the loss of a beloved companion animals.  Whether your state allows this is one of the first questions you should research. As of this writing, only a few states allow you to be compensated for this.