Necropsy: Searching for Answers

Whether your horse is a valued friend or a valued asset, the loss can be tough when he dies. But when your veterinarian presses you to get your horse necropsied, the thought of your horse's body being laid out, examined, cut up, and probed seems almost like a violation, prolonging the pain. What's the point?

There are several circumstances for which necropsy (animal autopsy) is recommended and of benefit to the horse owner:

  • To determine if a disease is infectious and could spread to other herd members;
  • To identify possible foreign disease or re-emergence of previously eradicated diseases;
  • To identify toxic substances;
  • To confirm or help identify a suspected or puzzling diagnosis;
  • To identify genetic disease; or
  • To help give the owner closure by determining the definitive cause of death.

"Necropsy would normally not be requested in cases such as a fracture or injury where the diagnosis is obvious," notes Nathaniel A. White II, DVM, MS, Dipl. ACVS, Theodora Ayer Randolph Professor of Surgery and Director of the Marion duPont Scott Equine Medical Center in Leesburg, Va. "But in the case of a colic or infectious disease, a necropsy may be helpful to diagnose a disease (or condition) and help prevent morbidity (illness) in other horses. Necropsies for fetuses are also important and should be completed as soon as possible so samples for viral isolation can be taken from fresh tissue. The placenta should also be examined if it is available."

Also, necropsies are helpful for evaluating the benefits of therapy or for insurance/ legal reasons, adds Neil M. Williams, DVM, PhD, Dipl. ACVP (American College of Veterinary Pathologists), associate professor at the University of Kentucky Livestock Disease Diagnostic Center in Lexington.

An insurance company might actually demand a necropsy in the case of death of an insured animal, and they have the right to do so, noted Fairfield Bain, DVM, Dipl. ACVIM, ACVP, ACVECC, of Hagyard-Davidson-McGee in Lexington. He says owners who insure their animals need to pay attention to the policy information and remember that the information obtained on a necropsy can be a help to everyone, including other horses on the property.

Taking a Look

All veterinary students are taught the basics of performing a necropsy, so any veterinarian can conduct a necropsy for examination of the internal organs and to collect tissue specimens for culture and microscopic evaluation. However, veterinary pathologists are specialists in performing necropsy examinations; they've completed advanced training in pathology, are board certified by the American College of Veterinary Pathologists, and thus are better able to make the procedure more accurate and informative, Williams says.

Adds White, "The microscopic evaluation, which is often equally important in making a diagnosis, is normally performed by a board-certified pathologist. The equine veterinarian who completes a gross examination will send the specimens of the suspected tissues or organs to a lab that has a certified pathologist to evaluate the microscopic slides."

The parts of the body that undergo examination depend on the suspected cause of death. "A routine necropsy usually includes dissection and visual examination of the heart, lungs, oral cavity (mouth), windpipe, skin, liver, spleen, kidneys, bladder, stomach, intestine, lymph nodes, abdominal cavity, adrenal glands, and mesenteric arteries," White says. "If nervous disease is suspected, the brain and spinal cord will be removed and examined. If toxicity is suspected, blood may be taken (if possible) and tissue samples may be saved for analysis. Other specific examinations would depend on the apparent disease such as joint, muscle, and hoof disease, or eye problems."

The exam is conducted in a systematic fashion that should be consistent from case to case in order to achieve the best results and to avoid overlooking important lesions.

"The history and clinical findings are first reviewed," says Williams. "An external examination allows detection of abnormalties in the skin and other external structures. Wounds, swellings, and other changes are noted. Next, a dissection is conducted in a systematic manner, noting abnormalities. Routine samples of organs and tissues and any abnormal-appearing tissues are taken, kept fresh and cooled, or placed in fixative for histopathology (microscopic tissue examination). Harvested samples are cultured for bacteria; fluid samples can undergo serologic testing. The liver, kidneys, stomach contents, blood, and urine can be tested for toxins, if indicated. Virus testing of tissue and fluids can be performed."

Complete necropsies take from one to several hours to perform. "The time is variable due to the nature of the problem, facility, and expertise of the individual performing the procedure," Williams says. "Cost varies by laboratory or veterinary practitioner performing the procedure, but usually can range from less than $100 to several hundred dollars."

Handle With Care

Necropsy should be conducted as soon as possible after death. Says White, "The carcass will decompose with time. This makes both gross and microscopic evaluation difficult. Horses that die in the summer will decompose rapidly if there is no way to refrigerate the carcass." Refrigeration is usually only possible at a hospital with a cooler or a diagnostic lab set up for large animals.

If the horse dies on the property and the owner wants the animal necropsied, it's important that the owner keep the body cool and, as soon as possible, schedule a veterinary call for necropsy at the farm or deliver the horse's body to a diagnostic laboratory, Williams says. "The horse can be loaded on a trailer or truck for transport to the diagnostic lab, if one is located in the area. Some areas have commercial haulers that will load and transport the body."

After the necropsy is completed, the body is usually buried (if necropsied on the farm), or is incinerated or rendered if the exam was performed at a laboratory, Williams relates. "In either case, local ordinances governing disposal should be adhered to." (See "After Goodbye", www.TheHorse.com/ViewArticle.aspx?ID=1520, for more information on carcass disposal.)

Bottom Line

"The actual necropsy is usually just the beginning of the process of arriving at a diagnosis," Williams emphasizes. "Some cases can be diagnosed with no further testing required (fractured leg, twisted intestine, etc.), but many cases require additional testing and histopathology to reach a definitive diagnosis."

Although the horse owner might be tempted to put a questionable death aside in order to move on more quickly from the loss, maintaining a big picture outlook might prevent further loss if there are other horses on the premises.

"A complete necropsy can produce valuable information regarding the cause of an unexpected, mystery death," underscores Williams. "With a necropsy, the veterinarian can determine the accuracy of the clinical diagnosis, provide feedback to the clinician regarding diagnosis and efficacy of therapy, help prevent future illness and losses in other horses on the farm, and identify emerging or reportable diseases, even those with human health risks."

About the Author

Marcia King

Marcia King is an award-winning freelance writer based in Ohio who specializes in equine, canine, and feline veterinary topics. She's schooled in hunt seat, dressage, and Western pleasure.

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