Clostridium perfringens type A (CpA) has been associated with serious gastrointestinal disease in young dairy and beef calves resulting in sudden death. CpA and other organisms have also been incriminated in hemorrhagic bowel syndrome (HBS), a sudden death disease that occurs in adult dairy cows.
CpA is a spore-forming bacteria that can remain in the environment and soil for many years. It is considered a normal inhabitant of the gastrointestinal tract of cattle and can be cultured from the feces of normal cattle that never get ill. CpA has the ability to proliferate very quickly, doubling its numbers in less than 10 minutes. This rapid growth contributes to the bacteria’s virulence by allowing it to quickly grow and reach numbers that may cause sudden death. The CpA bacteria secretes an alpha toxin that can cause cell destruction, hemolysis (breakdown of red blood cells), constriction of blood vessels and edema or swelling of the intestinal tissues.
Young dairy and beef calves
CpA enteritis in young calves causes acute signs of illness such as depression, bloating and colic (abdominal pain), which is followed by rapid death. Treatment is rarely successful. CpA organisms are a normal component of the gut bacterial population, but when excess starch or carbohydrates are present in the ration, the normal gut bacterial population can become unbalanced, allowing CpA bacteria to overgrow. The organisms begin to sporulate and secrete an alpha toxin, which causes intestinal damage. Excesses in starch or carbohydrates can occur with milk replacer mixing errors, the sudden growth of lush spring grass that can dramatically increase milk production, overfeeding or overconsumption of concentrates, such as in cases of grain overload in weaned cattle. Necropsy findings of dead calves may include purplish-colored small intestines, blood in the intestines or abomasal bleeding. There is no effective treatment once clinical signs appear, and death occurs rapidly after the onset of signs.
There currently is no commercially licensed vaccine for CpA, although USDA-licensed autogenous vaccines can be manufactured from samples containing the bacteria, which is obtained by a veterinarian from affected calves. The best samples to submit for diagnosis and/or vaccine production are liver and small intestinal tissues or swabs. Manure is not a suitable sample to submit because CpA organisms can be found in feces from normal, unaffected calves. The manufacture of an autogenous vaccine can take between six and eight weeks once samples are submitted. Seven- or 8-way commercially available clostridium vaccines do not provide adequate protection because they do not tend to contain sufficient levels of the causative alpha toxin. A common vaccination strategy is to vaccinate at-risk calves shortly after birth and then again as they are weaned.
Diagnosis
CpA enteritis is diagnosed by finding the typical lesions on necropsy as well as laboratory testing. Common lesions include enteritis with blood-filled loops of small intestine. The diagnosis is confirmed when the bacteria is cultured in the laboratory and the toxin is typed either by polymerase chain reaction (PCR) or through whole genome sequencing.
Control
Consultation with your herd veterinarian and vaccination with an autogenous CpA vaccine should be considered as part of an operation’s control strategy. Starch, carbohydrate and nutritional intake management should also be considered an important part of the management of herds that have experienced deaths due to Clostridium perfringens type A.
