Introduction:
Enterotoxemia caused by Clostridium perfringens type D affects sheep and goats of all ages (from one week to several years of age). There are two common times when this disease most often occurs. The first occurs when young animals nurse an abundant milk supply while grazing on improved pastures or being fed high quality hays and/or concentrates (grains). The second corresponds with the finishing or feedlot period where an animal is fed a high grain diet. Enterotoxemia is one of the most common causes of death in feeding lambs. In "explosive" outbreaks, losses may range from 10 to 40%. In unvaccinated feeder lambs, one can expect a minimum of 1% of the lambs to die from this disease, with an average death loss of between 2-2.5%.Causative Agent: The disease is caused by the bacterium Clostridium perfringens type D. It is normally present in low numbers in the bowel of most animals. Under circumstances brought about by heavy volume and high quality feeding, the organism grows rapidly and produces a powerful poison (toxin). This toxin is absorbed through the intestinal wall and causes death in a few hours. In many instances, deaths occur so quickly that owners do not observe sick animals. Any situation that causes a decrease in the movement of material out of the intestines will give the organism time to overgrow and produce lethal toxin levels in the animal. The following list identifies common conditions that can cause an animal to develop fatal enterotoxemia:
Clinical Signs: Deaths from enterotoxemia usually occur suddenly. In some cases, the animal may be sick for several hours or even a day or longer before it dies. Affected lambs and kids may experience neurological signs such as trembling, stiff limbs, and convulsive movements. Sometimes the animal becomes comatose, with death taking place quietly. Diarrhea may be present in some cases, particularly in goats.
While the symptoms described above are suggestive of enterotoxemia, they also may be seen in other diseases that cause sudden death, such as acute acidosis or grain founder, polioencephalomalacia, listeriosis, acute pasteurellosis, tetanus, and blackleg. Therefore, it is important that the cause of such deaths be promptly and correctly diagnosed.
Diagnosis/Treatment: A diagnosis of enterotoxemia is suggested when the sudden death of concentrate-fed animals that have not been vaccinated for Clostridium perfringens type D has occurred. Necropsy findings can also help lead to a diagnosis. If a necropsy or post-mortem is done immediately or shortly after death, few changes may be observed, particularly if the animal died suddenly. When changes are observed, they usually include congestion and fluid in the lungs, and an increase in fluid in the heart sac (pericardial sac) with clots of gelatinous material (fibrin). Small hemorrhages and blood splashes will be seen under the clear membrane which lines the outer and inner muscle walls of the heart. The tissues of the kidney can be filled with fluid and deteriorate rapidly. This is where the term "pulpy kidney" arises. The carcass decomposes rapidly and is distended with gas. Urine from an animal that died from enterotoxemia is usually positive for high levels of glucose (sugar) when tested. This disease can be confirmed by laboratory tests performed on the dead animal. It is wise to seek the counsel of a veterinarian to help in establishing a correct diagnosis and to outline control measures.
For some animals already affected, oral antibiotics (sulfas) can be beneficial. Because recognizing sick animals is difficult and treatment is often unrewarding, emphasis should be placed on prevention.
Prevention:
To prevent this disease, efforts should be focused on management and vaccination:
What to do in case of explosive outbreaks late in the feeding period:
Summary: Producers should be aware that enterotoxemia is not just a problem in animals being fed for market. This same disease can cause death in suckling (nursing) lambs/kids, older animals, or even in newborn lambs/kids before they are 36 hours old. The surest way to prevent this disease is to vaccinate against it.
There are other clostridial organisms that cause disease in sheep and goats. These are discussed on page F120.