– Dr. Michelle Arnold, UK Veterinary Diagnostic Laboratory
Ohio’s Diagnostic Lab is located at Reynoldsburg, OH
Sickness and death loss of farm animals is an unavoidable consequence of owning them. Whether it is one animal that dies unexpectedly or multiple animals developing symptoms of disease over a short span of time, most producers want to know the reason, the best effective treatment and how to prevent it. The local veterinarian should be the first person contacted to examine any sick animals and determine an appropriate treatment. The earlier the veterinarian is contacted in the disease process, the better the chance of instituting an effective therapy. However, in cases of sudden death or when disease appears to be spreading or in cases where treatment is ineffective, a veterinary diagnostic laboratory can help make a diagnosis and assist in development of a plan for treatment and control based on test results. The UK Veterinary Diagnostic Laboratory in Lexington (Web: http://vdl.uky.edu) and the Breathitt Veterinary Center in Hopkinsville (Web: https://breathitt.murraystate.edu/ ) are both full service laboratories serving the veterinarians and producers across the Commonwealth of Kentucky. Their websites contain complete, up-to-date access to all services offered as well as hours of operation, location, forms, and all other pertinent information. The submission form (also known as an “accession form”), needs to be filled out as completely as possible. This form as well as all other testing submission forms can be found on the web at: http://vdl.uky.edu/forms . To save valuable time and money, if there are any questions, call the laboratory ahead of time. A phone call to the lab prior to leaving the farm is never a bad idea to avoid any unforeseen circumstances.
Much useful information about an individual animal’s death and overall health issues in the herd can be gleaned from a necropsy (the animal equivalent of a human “autopsy”). During the necropsy, the veterinary pathologist will first open the animal and look for any visible abnormalities. This is called a “gross necropsy” and often gives an initial indication of the cause of death. Samples are then taken from all organ systems as well as blood and other bodily fluids and submitted to various laboratory sections for specific testing. In addition, sections of each organ (liver, lung, heart, kidney, brain, etc.) are cut into thin slices, processed, and placed on glass slides for examination under the microscope. It is under the scope, at the cellular level, that pathologists most often confirm the cause of death by recognizing the characteristic patterns of tissue damage resulting from a certain disease. Once the pathologist receives test results and looks at the slides, the pieces come together like a puzzle to arrive at a diagnosis. A plan can then be formulated with the producer and veterinarian to control and hopefully prevent the problem in the future. However, it is important to understand that autolysis (rotting) begins immediately after death and progresses rapidly, especially in hot weather. Rotten tissues make interpretation of tests and other lab findings very difficult if not impossible. Do bring dead animals to the lab within 24 hours after death, the sooner the better, for the best chance at an accurate diagnosis. Don’t bring live animals to the lab because euthanasia services are not offered. If euthanasia is performed prior to submission, don’t damage the brain if the animal has symptoms of rabies or other neurologic problem. Don’t show up at the lab after-hours with a dead animal without prior approval because there is no guarantee someone will be available to help unload and place the animal in the cooler. If timely submission to a diagnostic laboratory is not possible, the herd veterinarian can perform a “field” necropsy and take the necessary samples to send to the lab.
At the diagnostic laboratory, the tests ordered are based on initial necropsy findings and the “history” from the producer submitted with the dead animal. Simply put, the more information available about this animal and the herd, the easier and faster it is to narrow down the list of possibilities. Try to compile a complete “history” which is simply a snapshot of what the situation is on the farm, making sure to note anything out of the ordinary. Pictures and videos are worth a thousand words and can easily be added to the history by the staff at the laboratory. Be sure to indicate all treatments with antibiotics, recent vaccinations, etc., because these can impact test results and interpretation. The answers to the following questions will often yield useful information:
- A full description of this animal (breed, age, sex). If female, was she pregnant and did she have a calf on her? Was this animal raised on the farm or purchased? If purchased, when and where? Also, a description of the herd. How many cattle on the farm, how many in the group this animal came from and how many deaths have occurred in that group over what period of time? Are cattle in other groups and/or on different farms also affected?
- If sick when found, what symptoms were observed? Any pictures or videos taken? Was a vet contacted and/or treatment attempted? If found dead, when was the last time you saw the animal alive? Any signs of struggle at the time of death? Where was the animal found (for example, next to a pond)?
- When did this problem first begin? Have you ever had a similar problem on the farm? Are any other cattle showing signs of illness now?
- Vaccination history-what was given most recently and when?
- Summarize the diet currently being fed. Include what type of feed (grain) if offered and how much is consumed, forage available (hay/pasture/silage/baleage), and any tubs, trace mineral or salt available. Bring any feed tags or take pictures of labels from the bags or tubs. It is especially important to note any recent changes to the diet and when the changes were made. For example, have the cattle been without salt or mineral and were just given a new bag? Have they just rotated onto a new pasture? Is the water source a pond, creek, or stock tank? If it is a tank, is it city water, well water or pond/creek water? If a feed, forage, or water-related problem is suspected, do bring samples of those, too. However, don’t expect tests to be performed on every sample submitted unless the preliminary findings are pointing in that direction.
- Note when any new additions joined the herd, including replacement females, bulls, and calves and where they were purchased. Also note if any animals have been on the show circuit and, if so, when they returned to the farm.
- Is there recent history of contact with other animals? Any fenceline contact with neighbors’ livestock? Are there cats, dogs, rats, and/or wildlife in contact with your herd or their feed and water?
- Any recent bad weather events such as flooding, high winds causing down trees, lightning storms?
- Are there any junk piles, burn piles, compost piles, weed or yard trimmings in the pasture? Any sheds or old barns accessible to the herd? Are their woods available for the cattle to run in? Recent pesticide or herbicide use? Is there a road next to the farm where trash could be thrown over the fence?
Once the animal is submitted, don’t expect answers immediately. Some diseases are easily recognized but others are more challenging. Interim test results are sent from the lab periodically until a final report is issued. It can take as long as 2 weeks to generate the final report or even longer if any special tests were sent to outside laboratories. Questions about the final report can be addressed by the herd veterinarian or by the faculty and staff at the diagnostic laboratory.
It is important to understand that no veterinary diagnostic laboratory is 100% successful at figuring out every cause of death. To utilize a veterinary diagnostic lab most effectively, do come with fresh samples, pictures, or videos, and plenty of information. If a veterinarian examined the animal before death, be sure to let the lab personnel know so we can contact him or her for more information. By far, the most important factor for a successful diagnosis is minimizing the degree of autolysis (rotting) that takes place before submission. Getting the dead animal to the lab as soon as it is found or having a veterinarian euthanize an animal that is close to death and bringing it straight to the lab will markedly increase the effectiveness of testing. In cases of multiple death loss, do send more than one animal as it increases the odds of finding the inciting cause. In cases where a diagnosis is not found, don’t consider it a waste of time and money because many diseases may be ruled out with negative test results. However, rotten animals or those that have been scavenged are much more difficult to work with and often give disappointing answers.
