by: Stephen B. Blezinger
Ph.D., PAS

It happens. If you own cattle, at some point you will drive out in the pasture and you'll find one with all four feet in the air, or maybe very close to it. For stocker or backgrounding cattle producers who are accustomed to working with highly stressed, newly purchased animals either from the sale barn or from an order buyer 750 miles away this is not uncommon. Typical death loss rates (also known as mortality) are two to three percent. In some cases even higher. These producers know that there is a certain risk in dealing with these types of animals because they are stressed, immunocompromised or have been injured during the marketing and transportation process. They are aware of the risk, accept that and have a protocol for dealing with the problem. It is regrettable and while everyone works to minimize this issue as much as possible, it is a fact of life.

For the cow-calf producer, the most common losses are with new-born calves. Dystocia (loss of new calves) is also relatively common and every producer works to minimize this problem as well. Proper nutrition for the cow goes a long way to prevent dystocia, week calf syndrome, post-natal diarrhea and other conditions that may affect the new born calf resulting in its loss.

But what about the mature cow? Unfortunately from time to time producers will lose what was, for all practical purposes, a big, strong healthy cow. So then what?

Questions, questions . . . .

When the producer discovers a cow that has died a whole variety of questions comes into play:

1) What did she die of?

2) Did she have a calf that now needs to be cared for or dealt with?

3) Is she the only one?

4) Is there a possibility more can be lost?

5) What should be done now?

One loss is bad enough and has economic implications. If there is the potential for more losses because the cause is either health related and transmittable or if she ate something toxic that the others could likewise consume, there needs to be immediate action to prevent further losses. Then, in the long run, the body needs to be disposed of in some manner.

So let's examine some of the major questions.

What did she die of?

Often this question is simple to answer. She may have had trouble while calving and if in an area where no one was checking on heavy pregnant cows regularly, it happens. It may have been storming and she was struck by lightning. Again, not an uncommon occurrence and the signs are generally fairly obvious.

Some causes are more difficult to diagnose. If it were from disease of some type, having a veterinarian post (autopsy) the animal and take samples which are then sent off, generally to a diagnostic laboratory is the only way to determine what the condition or disease might have been. It can also help show where the “holes” are in the farm's animal health or vaccination program.

Another possibility is the ingestion of a toxic substance like lead from old car batteries or toxic plants. Consumption of high amounts of acorns (not uncommon in pastures where oak trees are plentiful or if forage is short) can be fatal. Grazing pastures that are high in nitrates (normally > 1.0 percent nitrate) or prussic acid (sorghum-type forages that have been cold or drought stressed) can be very toxic. Grazing winter pastures such as wheat, oats or ryegrass, if the cows are not prepared or if proper supplements (high magnesium minerals or similar) are not fed can lead to grass tetany or even hypocalcemia/milk fever. These conditions can be difficult to diagnose without extensive analyses. Grazing of clover pastures can lead to bloating which can also be fatal if not treated properly. Again, this is a fairly obvious condition.

Consumption of feeds and feed supplements can lead to animal loss. This generally occurs if the management of a given supplement is not correct. One of the most common causes of animal loss is urea poisoning or ammonia toxicity. This can occur when a cow consumes an excessive amount of urea in a short period of time. This most commonly occurs when hungry cows are allowed free access to feeds or supplements that are high in urea. This may be found in range cubes or other dry feeds, tub supplements which include high urea levels or liquid feeds. Urea inclusion as a source of nitrogen which the rumen bacteria convert to protein is very common and has been for years. It is a safe practice but care must be taken as to how these supplements are fed and excessive consumption is prevented. Again, this is not always easily diagnosed without veterinarian posting and tissue sampling.

Another possibility is sulfur toxicity from consuming feeds and forages high in sulfur (S). Excessive S in the animal's diet interrupts the bacteria in the rumen from producing the B-vitamin thiamin. The thiamin deficiency results in a neurological condition known as polioencephamolacia (PEM) which has more observable symptoms such as staggering, blindness and head-pressing (against immobile objects). Again this is a condition that can occur when consuming an overall diet for a period of time where the total S content exceeds around .5 percent. Certain feed supplements such as free-choice minerals liquid feeds, tub supplements of dry feeds high in by-products such as distiller's grains or corn gluten feed can all run higher in sulfur than .5 percent. When fed as a supplement with lower S feeds or forages dilutes the S down to non-problematic levels (<.35 percent) in the animal's overall diet. One aside, if the animal's diet exceeds .25 percent S it is known that the S level interferes with copper absorption by the formation of Cu-S complexes that are insoluble in the rumen and lower intestine and largely cannot be absorbed.

OK, I really don't know what she may have died of. . . . Getting the vet involved

If this is the case the producer has to ask a few more questions. Initially he or she has to decide if they need or want a veterinarian involved and incur that added cost. If the cause of the loss is obvious (cow lying bloated in a clover pasture, etc.), then no further action may be necessary than to dispose of the carcass and take steps to insure it does not happen again. If there is a possibility it could affect other animals, yes, the vet needs a call and asked to come out. If this is the case then one of the first things that needs to be determined before having the vet out is how long she may have been dead. If only a few hours then your vet can effectively post the cow, take tissue samples and send these off for analyses. If she has been gone a day or more the accuracy of autopsy or samples taken may be questionable. Remember, if the cause is not immediately discernible, there is always a potential risk to other animals in the herd. As such your vet needs to determine if the cause was health-related (related to a pathogenic organism), nutritionally related (consumption of something that lead to the animal's death, or toxicological (consumption of a toxic substance of some type.) There are screens/panels of tests including rumen contents, blood/serum enzymes and mineral values and so on, all of which are indicative of one problem or another.

Aside from the vet's efforts, other samples that should be taken and evaluated include pasture, hay and silage or haylage, and any feeds or supplements the animal may have consumed up until the time of death. These samples should be sent off immediately to a qualified feed and forage lab. In most cases the lab needs to run a wet chemistry analysis as this can provide the most accurate analyses of minerals. In most cases the macro minerals are of the greatest concern (Calcium, Phosphorus, Magnesium, Sulfur, Potassium). Some of the micros can cause a problems as well (particularly Copper and Selenium) but these generally take much longer to appear. For certain products, such as liquid feeds, not every lab has the capability of running an accurate analyses thus some homework is required to identify those labs with the right capabilities.

Furthermore, a close examination of the pasture or area she had immediate access to should be made. It is helpful to become familiar with toxic plants that are native to the area. Problems of this nature generally do not occur unless forages are in short supply.

Finally, taking the time to think through how that animal was managed, the pastures she was on and what she was fed is important. In many cases this can reveal that management may have played a significant role in her loss and care should be taken to avoid these practices in the future.


In many cases, diagnosis of a cause of death is expensive. The vet exam/post followed by lab analyses can run into the $100's of dollars. Because of this cost it is critical this process is handled correctly. Sampling, shipment and analyses of feed and forage samples can also be expensive.

It is a good idea to contact your veterinarian, pre-emptively and discuss these situations and what their normal charges are for a farm call, posting, sampling, shipment to the diagnostic lab, etc. A discussion concerning how your vet handles these situations are important since proper diagnosis can direct how the producer needs to handle things moving forward including changes in the health program, grazing practices, supplements fed and general management.

The same goes for the costs involving samples sent to a feed and forage lab. Locating a qualified lab as well as one that may deal with unique situations (such as the aforementioned analyses of liquid supplements) can save time and headache. Also, using a lab that can turn the samples around quickly is important. Generally the reports can be emailed or faxed. It also can help to have access to a trained, qualified nutritionist that can help you interpret the reports. This information should be considered alongside of a diagnostic lab reports. Above all, the goal is a quick, accurate diagnosis of the cause.

Overall, it makes sense to have a plan in place should losses of this nature occur. Hopefully it will not happen with any regularity but when it does, a protocol involving your veterinarian, a nutritionist, possibly extension personnel, anyone that can provide helpful, experienced input, is valuable in determining the cause of the loss. Also, having some familiarity with potential costs involved in this process can take some of the sting out of an already costly event.

Copyright May 2017 – Dr. Stephen B. Blezinger. Dr. Steve Blezinger is and nutritional and management consultant with an office in Sulphur Springs Texas. He can be reached by phone at (903) 352-3475 or by e-mail at sblez@verizon.net. For more information please visit us on Facebook at Reveille Livestock Concepts.

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