Hemorrhagic Bowel Syndrome in Swine
Hemorrhagic bowel syndrome demands our attention because in the past few years, we have seen it increase in occurrence without clearly identifiable reasons.
Some call it the “stealth bomber of swine disease.” It strikes suddenly, without warning. It kills quickly, often taking the best pigs. And it frequently leaves the producer wondering what struck his herd and why.
Hemorrhagic bowel syndrome (HBS), is a disease that seems to have just one devastating effect—sudden death loss in apparently healthy pigs. How can a producer guard against something that is totally unexpected, something that seems to come out of nowhere?
“We do have some clues and we do have strategies for dealing with hemorrhagic bowel,” assures Joseph F. Conner, DVM, of Carthage, IL. Conner is recognized on a global basis for his pioneering work in devising effective management strategies for such costly swine diseases as HBS, ileitis, clostridium and others.
From 1959 to 1970, it is reported that HBS accounted for only 2 to 5% of finishing pig mortality. Recent reports show an alarming trend documenting that up to 50% of finishing pig deaths are due to HBS in pigs 4 to 6 months of age, with barrows and gilts experiencing approximately equal incidence of the disease. If we knew in advance which pigs would break with HBS, our job might be a little easier. Unfortunately, we don’t get such indicators.
HBS suffers somewhat from an identity crisis in that it is often confused with the hemorrhagic form of ileitis. However, the two are quite different. Whereas HBS kills its victims and does not announce its presence in advance, pigs breaking with ileitis typically have bloody stools, weight loss and diminishing growth. Prevention is the only sure tactic we have to keep HBS at bay, while trying to understand the stressors that may trigger this disease seems to be the most promising direction for now.
Those stressors or risk factors might include disturbance in feed and water intake, or physical trauma, such as puberty-related fighting, horseplay and mounting. Breeding for longer carcasses also may be an indirect cause, as these generate additional cavity space, possibly leading to gastrointestinal problems. Other culprits may be allergic reactions to milk-based proteins, or infection from E coli. Salmonella and Clostridium. As for calendar timing, it has been established that HBS deaths are more likely to occur in summer.
For the time being, swine herd health experts admit they may be a long way from understanding the basic mysteries surrounding HBS death loss. One method many producers are trying to prevent the onset of HBS is a pulse regimen of BMD at 250 grams per ton in herds that have a history of HBS in market weight hogs.