Over the last two decades, the number of cows that die on-farm has continually increased. A survey in 1988 showed a mortality rate of 1.8 percent. The 2007 National Animal Health Monitoring System Dairy Study indicates a mortality rate of 5.7 percent for adult cows. This is more than a 300 percent increase in 20 years. In some states, adult cow mortality exceeds 10 percent per year.

The increase could be attributed to new diseases, genetics, nutrition, environment or management. To learn the true cause of death, a necropsy or autopsy must be performed. Research at Colorado State University indicates that the cause of death is misdiagnosed more than 50 percent of the time. “When we know the real reason cows are dying, we can start reversing the trend,” says Frank Garry, professor of veterinary medicine at Colorado State University.

Every dead animal has a story to tell, but the story cannot be told unless a necropsy is performed.

What went wrong?

It can be argued that time is better spent with live animals than dead animals, and disposing of carcasses after a necropsy can be a challenge. Yet, necropsies provide a level of insight into a herd’s health that cannot be gained anywhere else.

“If producers don’t know what really went wrong, they are just shooting in the dark. Did your treatment plan fail or were you treating the wrong disease?” asks Garry.

“We are fooling ourselves if we think we know why all cattle die. If you record a reason for death in your records without doing a necropsy, you are recording an educated guess at best,” says Angela Daniels, veterinarian at Circle H Animal Health in Dalhart, Texas.

How often are the right guesses made? The answer is less than 50 percent of the time. “Our practice held necropsy-training with a group of herd managers. They were asked to analyze the cause of death prior to the necropsy. Not a single cause of death was diagnosed correctly,” notes Daniels.

If incorrect assumptions are made, then the information stored in the herd’s computer is flawed, which brings another problem into play. When management evaluates death loss, computer records may say: “shot,” “dead,” “digestive,” “respiratory” or “injured.” But does the term “digestive” allow you to discriminate between salmonellosis, hardware disease or acidosis? Does it tell you anything you can base accurate management decisions on?

If you are trying to make decisions on how to reduce mortality with the data you have on hand, you will reach incorrect conclusions, says Daniels.

Find answers

Ideally, every dead animal should be necropsied. But, recognizing that dairy producers and veterinarians are busy, it is more realistic to use a targeted approach.

Target cows that performed poorly or died for unknown reasons. “If you guess that the majority of cows are dying from respiratory problems, and the results from a necropsy show they are dying from something else, this would substantially change the way you treat and manage those cows,” states Garry.

By targeting the necropsies, dairy producers can get a high return on their investment. Studies at Colorado State indicate that at least 50 percent of deaths could be prevented with proper management. Multiplied by the value of a replacement heifer, this is a huge economic opportunity.

Answers can be found in a short amount of time. The average necropsy takes 30 minutes to perform on adult cows, and less time for calves and heifers.

“If the information gained from a necropsy is put to use, it is an invaluable investment because you will be able to reduce your death loss,” explains Garry. The key, he says, is how the information is used.

Dee Griffin, veterinarian with the Great Plains Veterinary Educational Center at the

University of Nebraska, knows first-hand the value of necropsies. “Last fall, we had several cows die from what appeared to be pneumonia. After the necropsy, we learned they were dying from ketosis. In that stage of lactation, ketosis was not something we would have considered. We brought the nutritionist in to analyze the feed, and the ration prescribed was not what arrived from the feed mill. Because of the necropsy, we were able to fix the problem within 48 hours.”

La Luna Dairy, a 1,500-cow operation in Wellington, Colo., has been working with a veterinarian to perform necropsies for more than 10 years. Necropsies are performed on 90 percent of its dead animals. “Very often, we will find something unexpected and occasionally raise more questions than answers,” says owner Jon Slutsky. 

Necropsies have given Slutsky insight that he never had before. “We will call our veterinarian out at times we wouldn’t have in the past,” he says. “We also make culling and treatment decisions differently, because we have a heads-up to potential problems.”

Prior to performing necropsies, death loss at La Luna Dairy was as high as 9 percent, which meant the dairy was losing 135 cows per year for unknown reasons. Since implementing necropsies into its management practices, the dairy has been able to reduce death losses to 6 percent and hopes to reach 5 percent this year.

Determining the real cause of death is important in preventing future death loss and improving the health of the herd. Necropsies allow for the fastest detection of new problems on a dairy, and they help management focus on what needs to done to reduce death loss.

What is a necropsy? 

A necropsy, also called a post-mortem exam or autopsy, is an examination of a dead animal.
It is performed to obtain an accurate cause of death and, when done properly, involves looking at the animal as a whole, as well as looking at each individual organ within the body. Careful examination and sampling of organs helps determine the cause of death, whether it is by disease or trauma.

Educated guesses
More than 50 percent of cows that die are misdiagnosed. “Unless a necropsy is performed, the diagnosis made by the producer is at most an educated guess,” says Angela Daniels, veterinarian at Circle H Animal Health in Dalhart, Texas.

How do I perform a necropsy?

Necropsies should be performed within 24 hours of death, and it’s not always possible to have a veterinarian available on that short of notice.

But it is possible for a dairy producer or one of his or her employees to gather tissue samples for a veterinarian to evaluate. And with today’s technology, employees can perform a necropsy with a veterinarian on the phone. Or, digital pictures can be taken and discussed at a later date.

“Some information is better than no information,” says Garry. The key is to develop a broader group of people to perform a necropsy when a veterinarian cannot be there. As a result, the workforce will be more aware of unexplained deaths and do what it can to prevent them.

It is common practice in beef-cattle feedlots for personnel to perform necropsies and report
findings to a veterinarian.

Step-by-step tutorials on how to perform a necropsy are available online from Colorado State University and the University of Nebraska.

Or, you can order a CD by contacting Frank Garry, professor of veterinary medicine at Colorado State University, James L. Voss Veterinary Teaching Hospital, 300 West Drake, Fort Collins, Colo., 80523, phone: (970) 221-4535 or email: fgarry@colostate.edu

Work with your rendering facility

Disposing of a carcass after a necropsy can be challenging, as most renderers don’t like picking up these animals. However, the value received from a necropsy outweighs the challenges.

Dee Griffin, veterinarian with the Great Plains Veterinary Educational Center at the University of Nebraska, notes that it is possible to perform a thorough necropsy without cutting up the carcass. An intact carcass and quality hide are important to the rendering facility. From the rendering perspective, a carcass is worth $50 ($25 for the hide and $25 for meat and bone meal).

The instant an incorrect cut in the hide is made, the rendering facility loses money. A sharp knife is crucial to perform a necropsy without damaging the hide. And, carcasses should not be dragged, as this can ruin the value of the hide.

“Correct procedure should be followed so as not to make a mess of the carcass,” explains Griffin. “If body parts are falling out of the carcass, it becomes inconvenient and messy for the driver to pick it up, particularly if the weather is warm.”

“It is important to communicate with your rendering facility. Work together with the facility and driver so they receive value from the carcass and you receive value from the necropsy,” Griffin says.

Points to remember:

  • Give the rendering facility a good hide
  • Get the carcass to the facility fresh
  • Communicate with the rendering facility and driver
    about your plans
  • Treat the driver like you’re glad he’s there

Depending upon individual state regulations, carcasses can also be buried or composted.