Newborn calves can develop infection due to bacteria that proliferate rapidly in the gut and produce toxins. If this condition is not treated quickly and reversed, toxins get into the bloodstream and the calf goes into shock and within a few hours will result in death.
Warning signs are: severe gut pain (the calf is kicking at the belly region, or running frantically trying to get away from the pain, then collapses and thrashes on the ground) and-or sudden bloat.
This type of infection is called enterotoxemia, which literally means toxemia (presence of bacterial toxins in the bloodstream) from bacteria that are normally found in the intestine. Many, but not all bacteria that produce enterotoxemia are found in the intestine of healthy animals; they produce disease when certain conditions allow them to rapidly multiply.
The most common type of enterotoxemia in calves is caused by Clostridium perfringens, one of the Clostridia species found in the GI tract of livestock and passed in feces. These bacteria rarely cause gut infections in adult animals, but can cause fatal disease in calves. There are several types of C. perfringens, however, all these different types can affect calves in different ways, at different ages.
The alphabet killers - the types of C. perfringens that cause disease in cattle include types: A, B, C, D and E. These produce several major toxins. As stated by Dr. Francisco Uzal, Professor of Diagnostic Pathology, Uuniversity of California-Davis. The toxins involved are alpha, beta, epsilon and iota. Every type of C. perfringens produces the alpha toxin. The breakdown on which types produce which toxins is as follows: A-Alpha; B-Alpha, Beta and Epsilon; C-Alpha and Beta; D-Alpha and Epsilon; E-Alpha and Iota.
"These 4 toxins are called major toxins but there are many other so-called minor toxins. One of the minor toxins is called beta2, but it has nothing to do with the beta toxin except the name. All types of C. perfringens (A, B, C, D and E) may or may not produce beta2. There is also another minor toxin called CPE (Clostridium perfringens entertoxin). All of the types may or may not produce this one, as well - although CPE is mostly produced by type A strains. There are strains of type A, for instance that produce CPE and there are other strains that do not," explained Uzal. This complicates the picture.
Some of the type strains can thus be more damaging than others. "But in the case of beta2, no one has actually confirmed beyond doubt that this toxin has any damaging affect on cattle. This is a relatively newly discovered toxin, found in the late 1990s," Uzal said.
"The second minor toxin, CPE, is important in humans. It can be the second or third (depending on the year) most important cause of food-borne poisoning in humans. It causes diarrhea that lasts a day or two but usually does not require medical treatment - although there have been occasional fatalities in humans. The majority of 'food poisoning' cases in the U.S. are caused by E. coli, Salmonella or CPE," explained Uzal. CPE is not important in cattle.
In cattle the main players in producing intestinal disease are the major toxins produced by type A and type C. "Type C produces alpha and beta toxins. It produces disease in many animal species, mostly in the very young - because beta toxin is extremely sensitive to trypsin," said Uzal.
Trypsin is an enzyme produced by the pancreas and the small intestine. It breaks down proteins. "Trypsin is normally found in the GI tract and since it breaks down proteins it also breaks down beta toxins. Thus, trypsin is the natural defense against beta toxins. But newborn animals and human babies have very low levels of trypsin in the gut. If an adult consumes something containing beta toxin, trypsin will break it down. But babies of all species are more vulnerable. This is why type C can cause a disease in very young animals such as calves, piglets, foals, etc," stated Uzal.
This is why we vaccinate the dam ahead of calving, to create antibodies that will be in the colostrum immednately, and hope the calf nurses promptly.
"Type B contains alpha and epsilon toxins, and is traditionally the disease we see in sheep and goats - which is often called overeating disease. However, this particular disease has never been diagnosed in the U.S. Most cases have been reported in the Middle East.
Type B often proliferates in the GI tract when there are a lot of carbohydrates. When people talk about enterotoxemia in cattle they are usually referring to type D in older calves, such as in the feedlot, eating grain. However, this is also a rare form of enterotoxemia in cattle and I've only seen a handful of confirmed cases during the past 30 years," said Uzal.
"There are a few cases of type E reported, but they are also rare. This leaves type A as a more common possibility. If you look at the scientific literature, you see that most cases are thought to be caused by type A. But we are not able to confirm whether this really happens. The way we confirm the disease is to detect the toxin in the intestine. Type A produces only the alpha toxin. But every type of C. perfringens produces alpha toxin, and this toxin is usually found in the GI tract of normal animals, which makes confirmation of the diagnosis very difficult." It might be there anyway, and be perfectly harmless.
"So if we find type A in the three-month-old calf with an acute gut infection, we don't really know if the disease was actually caused by C. perfringens type A. It may be caused by some other toxin-forming bacteria," Uzal said. "I would advise ranchers who have cases of acute toxic gut infection in calves to have a thorough diagnostic work-up. Send a freshly dead animal to a diagnostic laboratory to perform a necropsy and investigate any possible cause of gut disease - including BVD, salmonella, E. coli, coronavirus, rotavirus, and so on. A stool sample can also be sent to the lab. Then we might at least find out what could be causing the problem."
"Here in California, we work with many big ranches, and when they see a calf going rapidly downhill, we ask them to bring it to us alive. Then we can put the calf down and have a very fresh body to work with," he stated.
Another possible cause of acute disease in calves might be C. difficile, which can cause acute and severe gut infection in newborn foals (and sometimes adult horses, and in other animal species). "We know very little about this in cattle, however. We are finding it in calves but since we also find it in healthy animals we don't know if it is actually causing the disease," Uzal said. "There may be a few other toxin-forming bacteria involved in acute gut disease in calves, including E. coli and maybe a few other organisms we don't know about."
It is very difficult, without laboratory diagnosis, to know what you are dealing with. Many bacteria, or even some viruses and parasites, can produce similar symptoms.
There is a vaccine for C. perfringens type A. There have also been a couple vaccines that include this; the United States Department of Agriculture approval.
Novartis has a conditional license for their type A vaccine. This vaccine might be worth a try, in some herds. Even if you don't know exactly what's causing a problem, if you use a vaccine and the incidence of disease is reduced, this may be a clue.
If a calf can be treated early - at the first signs of acute gut pain or bloat, there is a good chance of saving him. Infection can be halted with proper antibiotics, and the shutdown gut can be stimulated with castor oil to start things moving through again. Once the toxins get into the bloodstream, however, the calf quickly goes into shock and all the internal organs begin to shut down. At that point it's more challenging to save the calf.
Dr. Lee Meyring, cow-calf veterinarian at Steamboat Springs, CO said that if he suspects C. perfringens type C or D he gives the calf antitoxin.
"You can give it through various routes, including orally and intravenous. You can also give Banamine to help reduce the inflammatory reaction and ease the pain," Meyring said. "I usually give the calf oral penicillin, since this drug is very effective against clostridial organisms. It is most effective for this disease if put directly into the gut."
Another antibiotic that works for treating toxic gut infections is oral neomycin sulfate solution.
"If you do a necropsy on the calves that die, it's amazing how much of the intestine is dead. The bacteria multiply quickly and release massive amounts of toxins. This poison shuts down the gut almost immediately, " stated Meyring. "If a calf is bloated, I usually give him oil, to help get things moving through - if he's not so 'full' that there's no room for the oil."
Castor oil often works better than mineral oil, partly because you don't need as much volume (especially if the calf is already bloated and full) and it also stimulates the gut to move. Mineral oil merely works as a lubricant. The usual dose for castor oil is two-three ounces for a small calf, up to five or six ounces for a bigger two-three month old calf. You can't overdose a calf on castor oil, and it may help save him - by absorbing some of the toxins and stimulating the shut-down gut to move things on through.
Some calves are severely bloated, and some just have extreme gut pain, without bloating. "Some of these bacteria are tremendous gas-producers and some less - and this may be part of the difference," said Meyring. "At any rate, the castor oil stimulates things to move through."
Once the calf is in shock, however, the only chance for saving him is to give large amounts of intravenous fluids, along with medication to combat shock. If you can reverse this condition before vital organs are shut down or seriously damaged, the calf may survive. If you can reverse shock, and get enough fluid into the circulatory system to get the kidneys working, passing urine, the calf has a chance.