It is easier to use a vet you trust or find somebody who can give you a referral to a good vet than it is to sue a poorly performing vet. If the animal is valuable enough to sue over, insure it. When considering a lawsuit against a veterinarian, here are some things you should consider:

Veterinary malpractice cases are difficult for plaintiffs for two main reasons:

1) It is hard to find a veterinarian who will testify against another veterinarian; and
2) Animals are personal property.  You can't usually cannot recover pain & suffering   or damages based on the sentimental value. That takes the wind out of most plaintiff's cases right away.

The burden of proof in a veterinary malpractice action is always on the plaintiff.  
The plaintiff must prove:

1)      A veterinarian's acts or omissions failed to meet the standard of care;
2)      Acts or omissions were negligently performed;
3)      Negligently performed acts or injuries caused the animal's injury or death; and
4)      As a result, the plaintiff was damaged.

The professional duty of a veterinarian usually begins with obtaining a history of the animal (which assistants can be used to develop) and  a physical examination. The veterinarian is required to use professional leaning, skill, and care, beginning with the initial contact, the diagnosis of the problem, the decision and execution of treatment and follow-up care.  

In obtaining permission for treatment, there should be disclosure of the risk of the treatment or drugs. However, in one case where a horse died within fifteen minutes of being injected with a drug, the court held that there was no duty to disclose or warn when the odds of a lethal out come were 1 in 25,000. I think people bet on horses to win races with worse odds.

For example, Vet uses a  "punch" test rather than a rectal test as a preg check. The owner sold the cow for $170, rather than the $550. The issue was not whether the method of exam was done properly, but whether the appropriate test was used. Also, you have to proof the act caused the injury or death. If you are calling a vet, the animal is likely sick already. You have to establish that the vet's act is the reason for the injury or death, not just that the steer died when the vet gave it a shot.

For example,. Vet mixes the lye, sulphur and P&G soap wrong, treats dogs and dog die. Sheep dipped incorrectly and die. Vet loses in both the cases, as the act was done incorrectly.

Some of the other considerations against vets may include

1. Res ipsa loquitur.  Some mistakes are so obvious that the average person   can make an informed judgment . I was taught in law school that if you are arguing Res ipsa case for the injured party, you are arguing a loser.

2. Administrative Action for Malpractice. A person may file an action against a veterinarian with the state administrative licensing board that oversees veterinarians.

3. Negligence.  Iif the actions in question are not within the realm of malpractice, then there may be common negligence. For example, if a veterinarian was overseeing the loading of a bull into a head gate and did not properly secure  the head gate, the standard of care is that of negligence , not a professional malpractice claim.

4. Gross negligence.   If a dog came in for a treatment for heartworm check up, and the veterinarian removed a lung, that would be gross negligence. A claim of gross negligence may support different kinds of damage awards, but it just doesn't happen a lot. Again, super hard to prove and hard to find a plaintiff' s lawyer willing to take that on.

5. Intentional and negligent infliction of emotional distress (on the owner). This may arise when the actions (against an animal) are intentional and likely to produce a strong reaction in the owner. Iowa hardly recognizes it for people, I think it is a non starter for animal cases.

6. Duties of bailee. When a veterinarian boards animals they are acting as a "bailee" of an animal then legal liability may arise either out of negligent care of the animal or failure to redeliver the animal to the owner.  This is like when you give your coat to coat check, you aren't giving the coat away and you expect to be returned in about the same condition that you gave it to them. In one case, an insured veterinarian was bailee of an elephant "Sparkle", who died from poison while in his custody. A claim based upon a bailment does not require an expert witness.   

7. Violation of a contract obligation. This may be a useful approach if there is a written contract. However, oral agreements may also constitute a contract but are harder to prove. A contract claim can not be based on general statements of reassurance, i.e. "I will take good care of Sounder." Rather, it must be a specific promise to do something or obtain a specific result.  Again you are limited on damages.