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Hemorrhagic bowel syndrome: Trust your gut instinct

Nick Jenkins for Progressive Dairyman Published on 11 June 2018

One of the most frustrating situations for a dairy owner is to find a dead or dying cow and not understand the cause. In the case of sudden death, hemorrhagic bowel syndrome (HBS) should be considered, especially if you own a large, high-producing herd.

HBS is still a relatively poorly understood disease; in fact, results from the 2014 National Animal Health Monitoring System (NAHMS) survey indicated only 38 percent of operations said they “knew some basics” or were “fairly knowledgeable” about HBS.



HBS, which can go by several names such as bloody gut, jejunal hemorrhage syndrome, intraluminal-intramural hematoma or hemorrhagic enteritis, is a sporadic disease of adult dairy cattle characterized by bleeding in the small intestine, resulting in blood clots that obstruct the passage of feed material through the remaining gastrointestinal tract.

While HBS generally affects less than 0.5 percent of animals within a herd, it is a fatal and frustrating disease. Large herds, in general, are at greater risk for HBS because milk production per cow is generally higher, which requires increased dry matter intake (DMI) and elevated levels of fermentable carbohydrates.

Often, animals with this syndrome will be found dead or dying, and those noticed sooner will have one or more of the following symptoms: profound depression, weakness, anorexia, reduced milk production, elevated heart rate, abdominal distention, colic, dehydration, blood clots or frank blood in the manure, and a right-sided abdominal “ping.”

The “ping” is similar to what would be heard in animals with a displaced abomasum and is due to the gas production of bacteria within the obstructed intestines. In fact, some cases initially thought to be a right-displaced abomasum may in fact be cows with HBS.

Generally, medical treatment with antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDS) and supportive care is unsuccessful. More success is often seen with surgery where obstructing clots are manually broken down and devitalized tissue is removed. Even when aggressive treatment and surgery are attempted, the recovery rate is usually less than 50 percent.


There have been several theories on the cause of HBS, most notably Clostridium perfringens type A and Aspergillus fumigatus. However, all proposed agents have failed to cause the disease on their own when inoculated into healthy animals, and both organisms can be cultured from nondiseased cows.

This is because HBS is a complex disease process which requires several factors to be present before the disease manifests.

In the case of the most commonly proposed causes of HBS, C. perfringens and A. fumigatus, both are ubiquitous organisms found throughout the world and have been isolated from both healthy and diseased individuals. However, they are far more likely to be isolated in HBS cases than other healthy or non-HBS diseased animals.

The presence of C. perfringens and/or A. fumigatus in the feed or environment won’t normally cause disease until it undergoes rapid multiplication in the small intestine when conditions change to support its growth. This can occur when excessive carbohydrates are consumed.

Early lactation cows are more at risk due to increased risk of reduced gastrointestinal (GI) motility and immune function, as well as dramatically increased feed intake.

Risk factors that promote the conditions necessary for rapid multiplication of the offending bacteria are early to midlactation (80 percent of cases), second or greater lactation (90 percent of cases) and subacute rumen acidosis (SARA). SARA is often caused by high-energy diets that include highly fermentable carbohydrates and reduced levels of effective fiber, which promotes nutrient escape into the small intestine where it can be utilized by C. perfringens or other microbial organisms.


Prevention of HBS may never be 100 percent, but there are several nutritional and management strategies to minimize the incidence of HBS.

1. Focus on maintaining a healthy rumen and GI flora so that overgrowth of pathogenic organisms is minimized. This starts with balancing a diet with adequate effective fiber and moderating the levels of highly digestible carbohydrates to prevent rumen acidosis.

2. Focus on total mixed ration (TMR) consistency. A well-balanced ration on paper can be dramatically different than what the cow is consuming. If particle length is too long, sorting can occur, which increases the proportion of concentrates the cow consumes. On the other hand, if particle length is too short, the fiber present in the diet is less physically effective and does not provide enough substrate to support a healthy rumen environment.

3. Reduce the amount of slug feeding – cows consuming large amounts of feed in a short amount of time. Make sure feedbunks are cleaned regularly and feed is being pushed up frequently, minimize overcrowding and prioritize cow comfort.

4. Utilize the Penn State shaker box to determine if sorting of the TMR is occurring. A difference of 5 percent or less at each level, between fresh TMR and refusals, suggests sorting is not a major concern.

5. Review mixing errors. Errors in mixing the TMR can cause drastic changes in daily nutrient composition of the diet. This is important not just in prevention of HBS but in maintaining a consistent and comfortable environment for the cow on a daily basis.

6. Remove spoiled areas of feed ingredients to reduce the levels of molds and bacteria in the diet.

7. Focus on transition and early lactation cows. HBS occurs more frequently in early to midlactation. A smooth transition will minimize reductions in immune function and will limit the number of animals with concurrent diseases, which affect the rumen, GI motility and metabolic health.

8. Investigate the use of feed additives that can reduce the presence of C. perfringens and/or A. fumigatus with your nutritionist to determine if they make sense for your farm.

While the definitive cause of HBS is still not well understood, the primary organisms implicated are present in the environment and feeds of most dairy cattle. As is often the case, differences in host and environmental factors appear to be the main drivers of HBS cases as opposed to differences in the presence of microbial organisms.

Working with your nutritionists and veterinarians can help to reduce the number of HBS cases by finding areas of improvement in both nutrition and management that may be increasing the risk for HBS. Luckily, the changes that can reduce the risk of HBS are changes that positively affect rumen health and cow comfort, which can have positive effects on production, health and reproduction.  end mark

Standard Dairy Consultants provides nutritional and management consulting services and is a division of Standard Nutrition Company. Standard blends custom dairy mineral and vitamin supplements with facilities in the U.S. and Canada.

Nick Jenkins
  • Nick Jenkins, DVM, MS

  • Nutrition and Management Consultant
  • Standard Dairy Consultants