Performing necropsies could be a way for beef industry to improve survivability
March 29, 2019
Any time a calf dies, it is an expense. The question is, is there any value to the production system? Dr. Becky Funk, DVM, MS at Rushville Veterinary Clinic in Rushville, Neb., tells producers that she can still find value in the dead animal.
"Most of my toughest diagnoses on my toughest cases or herd outbreaks are unfortunately found on the basis of a dead animal. Once we lose one, I can do a lot more diagnostics than for an animal standing there looking at me wondering how I am going to treat it," she said.
Industry-wide, preweaning death loss in U.S. beef cattle harbors between 5 to 6 percent. Additionally, 2 to 3 percent of beef cow pregnancies will not yield a live calf, because it was either stillborn, aborted or succumbed to late fetal loss. "Of mortalities in preweaned calves, roughly 20 percent are due to unknown or undetermined causes. When cattle die, it is an opportunity for our industry. We're not always very good about finding out what kills our cattle," Funk said.
THE BIG PICTURE
Necropsy is the examination of the animal after death. Also called postmortem or post, it is a way to determine the cause of death in an animal, Funk said. The standard for finding the cause of death is either through a gross or full necropsy. The gross necropsy is opening the animal up and taking a look at big, high level things, like its organs, to visually ascertain what killed the animal.
"When we do a gross necropsy, we are looking at the big picture, but it does not involve lab diagnoses of tissues," Funk said.
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Obvious causes like a twisted gut, major trauma, stones in the urethra which ruptures the bladder, and congenital defects in the heart or intestine can be determined with a gross necropsy. "We can also use it as a follow-up on diseases impacting the herd, like pneumonia or scours," she said. "Everyone likes the gross necropsy because it doesn't cost that much. It doesn't require a lot of economic input, so producers feel like they can get a lot of bang for their buck if they can find an answer right there."
Full necropsies are more involved, and require either a veterinarian or one of their colleagues analyzing the animal and collecting samples to send to a laboratory. "It's warranted if you want to know the specific agent that caused that death, like pneumonia or if it is a pasteurella or BRSV," she said.
"It is also warranted when litigation is a possibility," she said. "If a lawyer is going to be involved or someone else is going to pay for the death, tell me up front because it makes a big difference. Instead of doing a gross necropsy to see what I think or form an opinion to save you some money, we are going to want to collect a full diagnostic sample. Things that usually involve litigation are toxins, feed errors or malicious intent. The downside of it is it can be moderately to extremely expensive to run full diagnostic samples on a necropsy."
"When people watch me do a necropsy, they probably don't realize I check every organ system in that animal," Funk said, while explaining to producers that most people have their own technique. "Everyone has a different procedure, but when you look at the big picture, things are always the same. The key is consistency. I don't do them the same as my partner, but I do them in the same order every time I do one. We go through everything in a systematic fashion so we don't miss anything."
Funks starts by recording an animal description and identification for that animal, especially if it is for an official report or insurance. The next step is to look at the physical appearance of the animal, and determine whether the hide is intact, if the animal has any discharge coming from the front or back, and what level the animal is decomposed. "It helps if you set up a level of expectations of what you can expect to get out of the necropsy," she said.
When the animal is opened up, it needs to be lying right side up, so the rumen is out of the way. A single cut is made from the anus to the chin, and the legs are reflected back. "When you open them up, look at the underside of the hide, and the muscles of the hip and shoulder. Look for bruising on the ribs, and any signs of external trauma," she said.
The animal should also be examined for any signs of fluid retention or swelling in the hindquarter muscles. "When an animal has severe bloat, the rumen acts like a cork primarily for the circulatory system. When you open the hips on a bloat, there will be a ton of fluid in there," she said.
The next step is opening the abdominal muscles and abdominal wall. Open the ribs and reflect them back. At this point, all the organ systems will be visible. Do an overall look to see if anything is abnormal.
When Funk performs a necropsy, she looks for specific things in specific sites like BVD lesions in the spiral colon, purple gut in the small intestine, coccidiosis in the large intestine and ulcers in the abomasum to try and diagnose why the animal died. Performing a necropsy is like being a CSI, Funk explains. "Necropsy is the gold standard for determining the cause of death and evaluating treatment failures," she said. ❖
— Clark is a freelance livestock journalist from western Nebraska. She can be reached by email at email@example.com.