Q&A: What Is a Necropsy?

An equine autopsy can not only help determine why a horse died but also can reveal factors that affected his health when he was alive.
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An equine autopsy can not only help determine why a horse died but also can reveal factors that affected his health when he was alive.

QI’d like to know more about equine autopsies. What exactly is involved? What do they cost and when are they appropriate?

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A: As a pathologist in this era of television-drama pseudoscience, I welcome the opportunity to dispel misconceptions about an equine autopsy, or, to use the veterinary term, a necropsy.

A necropsy is a very thorough examination of a dead animal either to discover the nature, magnitude and cause of a problem it had had in life or to determine why it died unexpectedly. For example, if a horse died or was put down while showing signs of colic, a necropsy might determine the source of the abdominal pain and the extent of any intestinal damage. However, if there were no signs of disease before death, a necropsy can provide the only clues that may explain why a horse died. Typically, a horse owner will have this done because it is a requirement of most insurance policies or for peace of mind. The cost is variable depending on whether you go to a state laboratory or a private diagnostic laboratory. State diagnostic labs tend to be partially subsidized.

The procedure is pretty straightforward. Before any animal is examined, a thorough history is needed. Usually, an owner provides this in written form. Sometimes, however, if the owner is present for the exam, the pathologist might ask a series of systematic questions to better understand the case.

Then the pathologist will carefully dissect the horse to get a clear look at nearly every part of its body. The contents of the abdomen and chest are thoroughly examined for abnormalities. Any lesions are recorded and sampled for further testing. The history is important as it helps us zero in on particular body systems that may be affected (for example, if your horse was head pressing, the brain and liver would be important body systems to evaluate).

The pathologist will collect multiple tissue samples, even those without obvious abnormalities. Some are frozen, but most are processed for examination under a microscope. Samples may also be sent to other laboratories to be tested for pathogens (bacteria, viruses, parasites) or toxicants.

At this stage, the remains of the animal are discarded according to the owner’s wishes. Most prefer that we dispose of the body by incineration or tissue digester systems. Cremation, and returning the ashes to the owner, is an option at some facilities. Only rarely will a lab release the unprocessed remains for home burial because of the potential hazards associated with cross-contamination by potentially dangerous organisms. 

The process is not complete until the collected tissues are examined with a microscope and any additional ancillary tests are returned. A completed report may take several weeks depending on what tests are bring run in addition to the initial necropsy. In the event of a sudden death, a final diagnosis or definitive explanation for why your horse died may not be possible even after this thorough examination.

Remember, pathologists are not coroners, so we do not issue death certificates. Our reports are considered legal documents and serve as the final word on attempting to explain an animal’s death, but your local veterinarian’s help will be needed to interpret and understand the results. 

Bradley Njaa, DVM, MVSc, DACVP

Anatomic Pathology

IDEXX Laboratories

West Sacramento, California


This article first appeared in EQUUS Issue #436.