Hemorrhagic Bowel Syndrome in Pigs

Hemorrhagic bowel syndrome (HBS) or necrotic enteritis was observed in only 2-5% of pigs at the beginning of fattening in Europe, and only in isolated cases in the United States from 1959 to 1970. In recent decades, the syndrome has become more prevalent throughout the world, both in newborns, weaned piglets, fattening pigs, and sows. It is described as sudden death of previously healthy, well-growing piglets with no noticeable clinical signs, since death occurs quickly, the contents of the intestine is with blood, the body is pale with a swollen abdomen, and diarrhea may be absent.

Hypothetical Causes of the Syndrome

No one can pinpoint obvious causes of the syndrome, but many microbiological studies focus on the presence of clostridia. A specific infectious agent cannot be isolated "as a cause" of hemorrhagic bowel syndrome, as there are always different pathogens on the farm and in the digestive tract of pigs. For the disease to develop, the pathogen needs certain conditions of the environment for reproduction or a sufficiently large number of them initially. It is known that prolonged and abundant use of fodder antibiotics has resulted in significant increase of clostridia due to intensive change of normal microflora in animals and in the environment, now in the feed, processing industry, and even in human food products (flour, chocolate, etc.). Hemorrhagic bowel syndrome (HBS) is usually stronger manifested in summer (gastric ulcers are also more common in this season), so it can be assumed that changes in external conditions (stress and temperature) lead to the development of the syndrome. Overeating and overflow of the intestine with food (large intervals between feedings, irregular feeding), insufficient intestinal motility, high protein level, or poorly digestible protein, inhomogeneous food particles (many small and several large particle sizes) suggest changes in the microflora of the intestinal tract. Liquid feeding is considered a specific factor for the development of the syndrome, as water and heat are conditions for every species of living creature, especially bacteria. A characteristic feature of clostridia is their ability to accumulate in all types of production lines and create a large clostridial background. Despite this, usually clostridia pass through the digestive tract in transit and leave the body in an unchanged (spore) state, if they do not find favorable conditions for transition into the vegetative phase. Under certain conditions, when a clostridium throws off the spore and begins to multiply, it releases toxins. Excessive reproduction of their specific strains leads to manifestations of the syndrome. The severity of HBS depends on how much spores will pass into the vegetative state, that is, will lose the shell, begin to multiply, and release toxins.


How to Control Hemorrhagic Bowel Syndrome in Pigs

As a rule, immunization of sows often does not help because due to different reasons there are not enough antibodies in the colostral milk acting against the clostridia toxins. With regard to disinfectants, there are a lot of speculations, and unfortunately they are attributed the properties of sporocicity, which they really do not feature. In fact, the chemical resistance of clostridia is very high and a lot of disinfectants are not effective against them (Chlorinated disinfectants have sporicidal and tuberculocidal activity, but clostridia spores remain in the lower layers of the buildups, where the disinfectants penetrate very poorly).

  1. 1)Feed digestibility
  2. 2)Feed and feeding lines hygiene


  1. 1)It is very important to ensure regular feeding and equip a sufficient feeding area at the same time for all pigs (Table 1). Competition during feeding increases the risk of overeating and overflow of the intestines. Dominating animals occupying places at the forage distributor grasp the first portions of dense fractions, and at the end of the trough the animals receive only the liquid fraction. It is important to place the distributor is in the middle of the trough, so that is distributes the homogeneous feed evenly along the entire length of the trough. For this, the pump must be of adequate power. Overflow of the gastrointestinal tract complicates its motor skills and protein digestibility. Insufficient motor skills or increased transit of feed to the thick section leads to the expansion of the intestine, damage to the capillaries, and decrease in blood circulation. Inflammatory processes in the intestines of different origin cause erosion of the mucosa, increase the amount of mucus and the pH of the contents, which initiates clostridia to pass into the vegetative phase. Under favorable conditions clostridia throw up the spores and begin to multiply, and after a few hours they can reach 108 -109 colony forming units (CFU)/g of contents, abundant colonies of bacteria invade the small intestine, secrete toxins and cause hemorrhagic bowel syndrome.

Table 1 Feeding area for pigs

Live weight (kg)

Table front, cm/head 6.7 kg of live weight

Trough width

(Distance between inner edges), cm



























  1. 2)Nevertheless, the key factor is the daily microbiological control of feed, feed lines, and digestive tract of pigs. Selective action on microorganisms (preserving lactic acid bacteria) allows maintaining a favorable balance of microorganisms and preventing the manifestation of hemorrhagic bowel syndrome and other diseases. Biocides and antibiotics inhibit the majority of microorganisms and open up opportunities for more resistant, dysfunctional forms of microbes. The ideal method for liquid feeding is to use substances suppressing the development of yeast and not affecting the growth of lactic acid bacteria. A certain mixture of organic acids, medium chain fatty acids, butyric acid and essential oils (developed by the INNOVAD Belgian company) successfully works on pig farms:

For the prevention of hemorrhagic bowel syndrome (HBS), the following scheme is used:

I) After switching to weaning, 1 week after medication with antibiotics, NOVION® L is administered through drinking water to reduce water pH down to 4.1 (10 consecutive days).

II) After switching to liquid feeding, NOVION® L is added to the liquid feed to reduce liquid feed pH down to 4.1-4.3 (10 consecutive days).

III) At the finish (50-85kg live weight), after medication with antibiotics, NOVION® L is added to the liquid feed to reduce liquid feed pH down to 4.1-4.2 (10 consecutive days) and after two weeks is repeated.


Table 2 The amount of yeast and fungi in the liquid feed of pigs

Натуральное брожение

Natural fermentation

Конкурентный продукт

Competitive product




NOVION® L is a liquid composition of a broad antimicrobial spectrum made from synergistically active substances. It controls pathogenic microorganisms in feed, drinking water, and in the digestive tract. In the digestive tract strengthens the intestine structure, increases the amount of digestive enzymes, reduces the food transit to the thick section and creates a healthy intestinal ecosystem.


By improving digestibility, feed and feeding lines hygiene, it is possible to successfully control hemorrhagic bowel syndrome and the number of clostridia. Antimicrobial substances have little effect on the spores of C. Perfringens, especially in the digestive tract of pigs, but all measures, increasing the number of lactic acid bacteria, improve the structure of the intestinal mucosa, secretion of digestive enzymes and activate the feed digestibility reduce the ability of clostridia to enter the vegetative phase and initiate the manifestation of the syndrome.

Back to articles list