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.