Abomasal Bloat and Abomasitis in Calves
Dave Van Metre, DVM, DACVIM
College of Veterinary Medicine and Biomedical Sciences
Colorado State University
Abomasitis is a sporadic disorder of young calves, lambs, and goat kids. Most affectedanimals are under 3 weeks of age. This disease is characterized by a fairly rapid onset ofabdominal distension, depressed attitude, and occasional signs of colic. Affected animals may beseen to grind their teeth and salivate. Diarrhea may or may not accompany these signs. Onceabdominal distension is severe, if the flank of the calf is shaken by hand, a tinkling and splashingsound may be heard. At necropsy, a gas-filled and inflamed abomasum is commonly seen. Theabomasum often contains foul-smelling, sour clots of milk, and bile reflux from the smallintestine may impart a greenish color to the abomasal contents. Hemorrhage from the abomasallining, however, may cause the contents to become rust-colored or even black. Theinflammation evident in the abomasal wall is the finding that prompts many to term this disease“abomasitis.” Ulcers may be visible in the abomasal wall, and occasionally, these perforate torelease abomasal contents into the abdominal cavity, resulting in peritonitis. Although there arenot a lot of descriptions of abomasal bloat in the veterinary literature, the proportion of affectedcalves that die appears to be well over 50-60%. Near death, calves show signs of shock,compromised respiration from the pressure of the distended stomach, and dehydration.
The cause(s) of abomasal bloat and abomasitis are not fully understood, and there arequite a few factors that have been proposed to be involved. Bacterial infection of the abomasalwall, compromised immunity from inadequate colostrum, ingestion of foreign bodies such ashair and coarse plants, and vitamin / mineral deficiencies have been proposed as factors involvedin the development of this disease. Specifically, vitamin E, selenium, and copper deficiencieshave been implicated as causative factors. Bacteria such as Clostridium perfringens type A andspecies of Sarcinia have been identified in the abomasum of affected calves. More recently,Salmonella typhimurium was isolated from the abomasal wall of Midwestern veal calves withabomasitis. Of these bacteria, only C. perfringens type A has been shown to experimentallycause the disease in calves; in 1988, investigators at the veterinary college at Kansas StateUniversity were able to recreate the disease in dairy calves by infusing C. perfringens type Ainto their stomachs. Interestingly, these investigators were able to create the disease in calvesthat were not copper-deficient. Belgian investigators have also detected C. perfringens in theabomasums of affected calves. The ability of this organism to produce gas from fermentation ofnutrients in the stomach is considered to contribute to dilation of the abomasum in affectedanimals. Clostridium perfringens type A is part of the normal bacterial flora of thegastrointestinal tract of cattle. The factors that trigger this agent to possibly act as a pathogenicbacteria remain uncertain; however, certain strains make large quantities of toxins. Further, thenumbers of this organism in the gut have been shown to increase when cattle ingest largeamounts of easily digestible carbohydrates and protein (such as milk or lush grass).
Cases of this disease in beef calves have occurred soon after management practices thatcause delays in regular nursing patterns or changes in environment that interrupt normal nursingpatterns (e.g. winter storms). In dairy calves, poor milk hygiene, intermittent feeding of largevolumes of milk, and cool milk temperature are considered to be potential contributory factors. The common thread seems to be ingestion of a larger-than-ideal milk meal. This may result in aslowing of stomach emptying, which may then enable the bacteria to ferment the milk and creategas. Given the multitude of contributory factors proposed to date, it is possible that this diseaseoccurs when multiple factors occur together.
Treatment of this disease has mixed results. Early intervention is critical. At the CSUveterinary hospital, when presented with a calf with abomasal bloat, our first step is to preventfurther suckling and to not tube the calf with anything that might trigger further bacterial growthand gas production in the stomach – in other words, no glucose-containing oral electrolytes,milk, or milk replacer is fed until the calf has recovered. Passage of a stomach tube while thecalf is recumbent or standing often does not relieve the bloat because the gas is trapped in thefourth stomach (the abomasum) and the tube only enters the first two stomachs (the rumen andreticulum).
A different method for passing the stomach tube may relieve the bloat in affected calves.The length of tube necessary to reach the stomach is typically the length from the mouth to thelast rib on the calf’s side. Once the tube is in place, a helper can lift the front end of the calf upso that the calf is sitting or standing in a near vertical plane – this may cause the gas to percolateup into the rumen and reticulum. The tube should be gently moved back and forth several incheswhile the calf is held in this position. Gentle pressure or massage of the calf’s flank mayfacilitate gas release. The holder should listen or smell for gas release, or place the free end ofthe tube in a cup of water to see the bubbles that indicate that gas is being released. Before thetube is removed, procaine penicillin (10 cc of 10,000 IU/ml solution) mixed in 2 cups of mineraloil should be administered into the tube, with a cup or two of warm water as a “chaser” to pushthe medication out of the tube and into the stomach. This step is intended to slow bacterialfermentation of milk nutrients into gas. Subcutaneous administration of procaine penicillin (4 ccof 10,000 IU/ml solution per 100 lbs of bodyweight, 1-2 times per day) is also recommended, assome invasion of the abomasal wall by bacteria may be occurring. Calves also appear to benefitfrom intravenous or subcutaneous fluids and an injection of 50-100 mg (1-2 ml) of intravenousor subcutaneous flunixin meglumine (Banamine®). Intramuscular administration of this productshould be avoided as it causes considerable muscle damage. Consult your veterinarian for othertreatment options such as abomasal decompression.
Because the cause(s) of abomasal bloat and abomasitis are not well proven, preventivemeasures are currently based on a “best guess” as to what is going on to set these calves up forthis disease. Certainly, one must consider whether or not the nutrition of the pregnant cowcould be involved. Protein, energy, vitamin, and trace mineral problems should be identified.Management steps to ensure adequate colostral intake by newborn calves is a must. Because thefermentation of milk by bacteria seems to be the source of gas, one must consider environmentalor management factors that may trigger changes in the volume of milk ingested by a hungry calf.Management practices that cause prolonged interruption of suckling must be made time-efficientin order to limit engorgement of the udder and subsequent ingestion by the neonate of a largerthan-normal milk meal. Sudden and severe changes in weather may cause dams and theiroffspring to seek shelter or remain recumbent for prolonged periods of time. In such instances,when the weather clears or daybreak occurs, the dams then stand up – and the hungry calf is thenpresented with an engorged udder. This can be remedied by providing multiple locales for shelter and bedding, or simply encouraging dams to stand up and eat by providing hay (weatherpermitting). This practice may encourage the dams to stand, thereby enabling more frequent,lower-volume nursing than if the cattle were left to “sit the storm out.” Group penning,inadequate fiber diets, and ectoparasites may trigger hair chewing by calves, and hairballs thatform in the abomasum may irritate the lining and trigger the disease.
Currently, there is no clear data on whether or not conventional vaccines that include theinactivated toxins from C. perfringens types C and D induce antibodies in the colostrum thatprotect the calf from disease caused by C. perfringens type A. The degree to which crossprotectionagainst type A occurs may vary by the manufacturer of type C and D vaccines. Checkwith your veterinarian, as he or she may request data on cross-protection from the vaccinemanufacturer. A commercial vaccine that induces antibodies against the major toxin of C.perfringens type A is currently available; however, its efficacy in prevention of abomasal bloat /abomasitis is currently unproven. This is a troublesome disease that can flare up without anyapparent predisposing cause. Please feel free to contact members of the CSU beef team withquestions about this or other health problems of neonatal calves.