A No Brainer by Mike Mehren Ph.D.

A No Brainer
BY MIKE MEHREN

“Brainer” is a term used by cattle folks to describe a disease known as polio encephalomalacia (PEM). It causes the cattle to twist their head to the side, stagger, go blind, and go down. It is caused by factors that prevent the production of thiamine in the paunch. There is evidence that some feeds can be a factor, and an excess of the mineral sulfur has been identified. I believe that molds may also be related because of their effect on the bugs in the paunch. It can occur during any season of the year, and out on pasture as well as in the feedlot. PEM can also be caused by lead toxicity, sodium (salt) toxicity and lack of water.

We commonly state that cattle do not need to be fed any of the B Complex Vitamins. This is because they are produced in the paunch, and when the animal swallows the microbes from the paunch, B vitamins are digested from the microbes. This particular disease is good evidence that cattle, sheep, and other cud-chewing animals have a requirement for the B Vitamins, but under normal circumstances they do not have to be supplied in the feed. B Vitamins are very important for the normal use of proteins, carbohydrates, and fats. They are parts of many enzymes that break down the feed into something that the body can use. High producing dairy cattle are fed B vitamins. Three that come to mind are niacin, choline, and biotin. Baby dairy calves are also fed B vitamins before their paunch becomes functional at about 8 weeks of age. As the beef industry continues to ‘push the envelope’ further with biotechnology and genetic engineering, we will probably find situations where feeding B vitamins become standard practice. When animals are sick or off feed we give them products that are designed to stimulate the microbes, so that they grow actively and digest feed. These preparations may be in liquid, gel, capsule, meal, or paste form. Most contain sources of B vitamins. The B vitamins may come from yeast, bacteria or they may be in the form of the vitamin itself, such as niacin and riboflavin.

There are two schools of thought on the cause of PEM. One line of thinking is that thiamine is broken down by thiaminase enzymes in the paunch. The thiaminase can be produced by microbes in the paunch, or may come from the diet. When this happens there is a deficiency of thiamine available to the animal. The other theory relates to excess sulfur that may come from the diet and water source. Excess sulfur in the paunch is converted to the toxic gas hydrogen sulfide. Feeds such as distillers dried grain, turnips, and molasses are all quite high in sulfur. Weeds such as lambsquarter, kochia, and Canada thistle also accumulate sulfur. PEM outbreaks occur when animals are under stress due to extreme weather changes and can also occur during a ration change in the feedlot. Moving cattle from dry range to lush irrigated turnips or triticale also constitutes an extreme ration change. PEM can be chronic where there is a gradual decline in thiamine, but the only kind I’ve seen is acute...where the deficiency is severe and the animals show symptoms within days after exposure (whether it’s high sulfur or lack of thiamine).

Like other nutritional diseases such as bloat and grass tetany, it is difficult to conduct research on the exact cause of PEM because not all the animals will show symptoms of the disease when others will become quite ill and die without treatment.

The treatment most commonly used is an injection of thiamine. This seems to work even when subsequent investigation shows a high level of sulfur intake. The response can be very dramatic; from being down to up and going within minutes. Sometimes it takes several hours, or a second shot, and sometimes it’s too late. PEM causes damage to the brain, and once that has occurred it is irreversible. Even if treatment with thiamine is successful it isn’t a bad idea to check sulfur content of the feed and water. Dietary sulfur should be no more than 0.3%. The level of sulfur that may cause problems is 0.4% and the amount of sulfate in the water must be included in the total sulfur intake. Feed testing labs routinely test for sulfur, but it is not always included in the ‘package’ that tests for many nutrients at one time. You may have to request sulfur analysis individually. I routinely ask for sulfur analysis when checking on copper problems, because a high level of sulfur ties up copper. I have several clients whose cattle graze turnips. Years ago we had a serious outbreak of PEM and following that episode decided to add thiamine to their mineral. We continue that practice now and whether it continues to provide protection is unknown, however we haven’t had PEM since that time. In another instance, yearlings were grazing grass and we had a slug of deaths all of a sudden. We never found live cattle, so had no symptoms to observe. After quite a bit of investigation we found an old ‘battery dumping site’ in a far corner of the pasture the cattle were grazing. No one noticed this area when checking the cattle or the fences. It looked like the batteries had been nosed around and possibly licked. Tissue samples from some of the dead cattle showed high levels of lead and the brains had definitely been traumatized. That was the first instance of lead poisoning that I had seen; the vet said that if we saw any of them alive, they probably would have had the same symptoms as PEM.

Since salt toxicity has symptoms that are similar to PEM it might be worth mentioning here. Salt toxicity is very rare, but does occur. When it does, it’s pretty disastrous because many animals are involved. What usually happens is that the animals have had no salt for an extended period of time. This might be spring and summer grazing in the mountains. We don’t want the elk and deer to eat any of our precious salt, so we don’t feed any. We know that the cattle need salt, but figure they’ll probably get enough in the forage. Other than saltgrass, very few forages in the Pacific Northwest have any appreciable amount of sodium. However, just to make sure we put loose salt out in a big trough, so that the animals can get their fill when they are moved to fall range. There is no water where we unload the cattle, but there is a spring about ½ mile down the canyon. Cattle do have a ‘nutritional wisdom’ for salt. When cattle are salt hungry they will actively seek out a source of salt. In this particular instance they didn’t have to seek very far, it was right in front of them when they were unloaded. Twenty three cows died within six hours between the trough and the spring. One hundred cows had eaten almost 250 lb of salt in less than six hours. If there had been water in the corral where the cattle were unloaded, they probably would have been fine. Cattle can consume huge amounts of salt as long as they can dilute it with a large volume of water. We use this phenomenon when we limit the intake of a self-fed supplement by adding salt.

As we venture into an era where new feed sources may replace the old standards, it will pay to learn as much as possible about the nutrient content of the new feed. Hint, Hint,
Hint...have the feed analyzed before you feed so that you can anticipate problems before they hit your herd. Diseases such as PEM can be treated successfully if the symptoms
are seen early in the onset of the disease.

Michael J. Mehren Ph.D. is a livestock nutritionist who thinks feed testing is a ‘no brainer’. He can be contacted by Email at mehrens@eotnet.net.



		A No Brainer BY MIKE MEHREN “Brainer” is a term used by cattle folks to describe a disease known as polio encephalomalacia (PEM). It causes the cattle to twist their head to the side, stagger, go blind, and go down. It is caused by factors that prevent the production of thiamine in the paunch. There is evidence that some feeds can be a factor, and an excess of the mineral sulfur has been identified. I believe that molds may also be related because of their effect on the bugs in the paunch. It can occur during any season of the year, and out on pasture as well as in the feedlot. PEM can also be caused by lead toxicity, sodium (salt) toxicity and lack of water. We commonly state that cattle do not need to be fed any of the B Complex Vitamins. This is because they are produced in the paunch, and when the animal swallows the microbes from the paunch, B vitamins are digested from the microbes. This particular disease is good evidence that cattle, sheep, and other cud-chewing animals have a requirement for the B Vitamins, but under normal circumstances they do not have to be supplied in the feed. B Vitamins are very important for the normal use of proteins, carbohydrates, and fats. They are parts of many enzymes that break down the feed into something that the body can use. High producing dairy cattle are fed B vitamins. Three that come to mind are niacin, choline, and biotin. Baby dairy calves are also fed B vitamins before their paunch becomes functional at about 8 weeks of age. As the beef industry continues to ‘push the envelope’ further with biotechnology and genetic engineering, we will probably find situations where feeding B vitamins become standard practice. When animals are sick or off feed we give them products that are designed to stimulate the microbes, so that they grow actively and digest feed. These preparations may be in liquid, gel, capsule, meal, or paste form. Most contain sources of B vitamins. The B vitamins may come from yeast, bacteria or they may be in the form of the vitamin itself, such as niacin and riboflavin. There are two schools of thought on the cause of PEM. One line of thinking is that thiamine is broken down by thiaminase enzymes in the paunch. The thiaminase can be produced by microbes in the paunch, or may come from the diet. When this happens there is a deficiency of thiamine available to the animal. The other theory relates to excess sulfur that may come from the diet and water source. Excess sulfur in the paunch is converted to the toxic gas hydrogen sulfide. Feeds such as distillers dried grain, turnips, and molasses are all quite high in sulfur. Weeds such as lambsquarter, kochia, and Canada thistle also accumulate sulfur. PEM outbreaks occur when animals are under stress due to extreme weather changes and can also occur during a ration change in the feedlot. Moving cattle from dry range to lush irrigated turnips or triticale also constitutes an extreme ration change. PEM can be chronic where there is a gradual decline in thiamine, but the only kind I’ve seen is acute...where the deficiency is severe and the animals show symptoms within days after exposure (whether it’s high sulfur or lack of thiamine). Like other nutritional diseases such as bloat and grass tetany, it is difficult to conduct research on the exact cause of PEM because not all the animals will show symptoms of the disease when others will become quite ill and die without treatment. The treatment most commonly used is an injection of thiamine. This seems to work even when subsequent investigation shows a high level of sulfur intake. The response can be very dramatic; from being down to up and going within minutes. Sometimes it takes several hours, or a second shot, and sometimes it’s too late. PEM causes damage to the brain, and once that has occurred it is irreversible. Even if treatment with thiamine is successful it isn’t a bad idea to check sulfur content of the feed and water. Dietary sulfur should be no more than 0.3%. The level of sulfur that may cause problems is 0.4% and the amount of sulfate in the water must be included in the total sulfur intake. Feed testing labs routinely test for sulfur, but it is not always included in the ‘package’ that tests for many nutrients at one time. You may have to request sulfur analysis individually. I routinely ask for sulfur analysis when checking on copper problems, because a high level of sulfur ties up copper. I have several clients whose cattle graze turnips. Years ago we had a serious outbreak of PEM and following that episode decided to add thiamine to their mineral. We continue that practice now and whether it continues to provide protection is unknown, however we haven’t had PEM since that time. In another instance, yearlings were grazing grass and we had a slug of deaths all of a sudden. We never found live cattle, so had no symptoms to observe. After quite a bit of investigation we found an old ‘battery dumping site’ in a far corner of the pasture the cattle were grazing. No one noticed this area when checking the cattle or the fences. It looked like the batteries had been nosed around and possibly licked. Tissue samples from some of the dead cattle showed high levels of lead and the brains had definitely been traumatized. That was the first instance of lead poisoning that I had seen; the vet said that if we saw any of them alive, they probably would have had the same symptoms as PEM. Since salt toxicity has symptoms that are similar to PEM it might be worth mentioning here. Salt toxicity is very rare, but does occur. When it does, it’s pretty disastrous because many animals are involved. What usually happens is that the animals have had no salt for an extended period of time. This might be spring and summer grazing in the mountains. We don’t want the elk and deer to eat any of our precious salt, so we don’t feed any. We know that the cattle need salt, but figure they’ll probably get enough in the forage. Other than saltgrass, very few forages in the Pacific Northwest have any appreciable amount of sodium. However, just to make sure we put loose salt out in a big trough, so that the animals can get their fill when they are moved to fall range. There is no water where we unload the cattle, but there is a spring about ½ mile down the canyon. Cattle do have a ‘nutritional wisdom’ for salt. When cattle are salt hungry they will actively seek out a source of salt. In this particular instance they didn’t have to seek very far, it was right in front of them when they were unloaded. Twenty three cows died within six hours between the trough and the spring. One hundred cows had eaten almost 250 lb of salt in less than six hours. If there had been water in the corral where the cattle were unloaded, they probably would have been fine. Cattle can consume huge amounts of salt as long as they can dilute it with a large volume of water. We use this phenomenon when we limit the intake of a self-fed supplement by adding salt. As we venture into an era where new feed sources may replace the old standards, it will pay to learn as much as possible about the nutrient content of the new feed. Hint, Hint, Hint...have the feed analyzed before you feed so that you can anticipate problems before they hit your herd. Diseases such as PEM can be treated successfully if the symptoms are seen early in the onset of the disease. Michael J. Mehren Ph.D. is a livestock nutritionist who thinks feed testing is a ‘no brainer’. He can be contacted by Email at mehrens@eotnet.net.		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