The loss of an animal that you have been caring for is never an easy pill to swallow, especially if there was little or no warning of the potential loss of life. Death that occurs suddenly and without warning often leaves owners with many questions and few clues that would lead to an explanation. The International Camelid Institute, along with many other veterinarians, has often been asked to explain sudden death. This is typically when the discussion of post-mortem exam arises. Discussing the disposition of a loved animal's remains is difficult at such an emotional time, so it seems a pre-emptive discussion of the details and importance is prudent. Veterinarians can provide no reliable information on the cause of an animal's death if no post-mortem examination is done. These exams are preferably done by a pathologist at a diagnostic lab, but on-farm examinations can be informative. Veterinarians are frustrated when we are asked to explain why a farm has lost four llamas or alpacas over the past year, but no diagnostic tests or post-mortem examinations have been performed on any of them. Post-mortem literally means after death. So, a post-mortem examination, or sometimes called necropsy, is the examination of an animal's remains after they have died. Veterinarians do not use the term "autopsy" because that refers specifically to examination of humans after death. The timing of these exams is critical to the ability of a pathologist or veterinarian to interpret their findings. Decomposition starts immediately after death and the rate is based on the climate that the body has been stored in: heat and humidity accelerate the decomposition process. When an animal dies or a fetus is aborted and post-mortem exam has to be delayed, refrigeration of the body and fetal membranes is required. Freezing significantly alters tissues and should be avoided. Not many people have access to a large enough refrigerator for an adult camelid, so call a veterinarian immediately if you are considering a necropsy exam on your animal. If you are fortunate, you will have access to a veterinary school or diagnostic laboratory. That can be a particularly attractive option for those that have the unfortunate responsibility of dealing with the remains of a departed animal. Why is it necessary to thoroughly examine the remains of an animal that died for unknown reasons? Why can't my vet just tell me what happened? The fact is that many of the "symptoms" that are described at the time of death, such as seizures, do not necessarily have anything to do with the cause of death. Pre-death seizures can simply be what we call agonal signs; things the body does as a result of dying. The lists of diseases and conditions that can cause sudden, unexplained death in an apparently healthy animal are extremely lengthy. Sometimes you get lucky and find evidence on external exam, but internal and microscopic examination is required in nearly all cases. When there are other animals on the farm, many people want to try to make sure that their other animals are not at risk before others are affected, and nobody can assess the risk to the other animals when they don't know why the first one died. Additionally, attempts to determine cause of abortion or pregnancy loss also must be similarly investigated. One of the comments we hear is, "they can never tell me the cause". Remember, a negative finding on necropsy is just as significant as a positive finding. It is frustrating to know the cause of death in that one animal, but a "negative" necropsy exam has tremendous benefit in trying to determine rule-out diagnoses, especially for future problem cases. What about plant toxicity or intentional poisoning? In this situation, the investigation includes a list of suspected culprits and a toxicology analysis. The contents of the stomach are required in these situations, but in the situation where long term, chronic ingestion of toxic plants or poisons are involved then other samples will need to be taken and analysed. In veterinary medicine, there is no such thing as a "tox screen". Testing blindly for any possible toxin would cost tens-of-thousands. You have to know what you want to test for and you have to ask for it specifically. Thus, it is crucial to discuss the case with a specialist in animal toxicology to determine a list of "reasonable" guesses. Some diagnostic labs might make some recommendations based on their previous experiences with toxic plants and poisonings in your area during a given season, but some will not. Sometimes post-mortem exam reveals a long standing chronic problem that went undetected. Some animals are particularly stoic and don't show signs of illness for fear of appearing weak to predators. In some instances, illness that progresses slowly over time will allow an animal to "compensate" and no illness will be detected by the owners. As an example, anemia or too few red blood cells can get extremely severe if it occurs over a long period of time, such as is the case in severe parasitism or other chronic illnesses that affect red blood cell production. Normally, an animal's blood will be around 30% red cells, we have seen animals that are still functional with red cell counts as low as 4%. If you quickly removed that much blood from an animal, they would die, but if it happens slowly over time, then you might not see any evidence until the animal is critical. In a situation where parasites are to blame, then the other animals on the farm might be at risk and this would be a situation worth investigating. Of course, there are always situations were something catastrophic, but isolated occurs to an animal that was either not preventable or untreatable. For example, lightening strikes or other electrocutions, rupture of major blood vessels due to aneurysms or other anatomical anomalies, severe head traumas, and other sorts of things that would be unlikely to afflict others in the herd. In these situations it is worth the piece of mind to know that the others are not likely to be at risk and that you couldn't have prevented the outcome. Some post-mortem exams or necropsies do not reveal the cause of death. This is frustrating for both the owner or caregiver and the veterinarian doing the exam. We all prefer to have a solid explanation, it makes us feel more in control. However, we can not emphasize enough the necessity of post-mortem exam on every death and every abortion. If you look you might not find anything. If you do not look, it is predetermined that you will learn nothing. Not to try is inexcusable; to try and fail is a part of life. We recommend that every death, every stillborn, every abortion should be examined by a pathologist every time. Tracy Miesner, DVM
David E Anderson, DVM, MS, DACVS
International Camelid Institute
www.icinfo.org
Classical MileEnd Alpacas - enquiries@alpacauk.co.uk - 01884 243 579 |
