Profit-robbing swine dysentery (more commonly known as bloody scours) is a problem that Dr. Mark Hammer says pork producers don’t have to live with these days. With conservative estimates at losses of $5 a pig up to more realistic projections of $10, Hammer can’t understand why this disease is still rearing its head in modern pig production.
“Swine dysentery is a very costly disease but because of how we’re raising pigs now in three-site production the clinical presentation has changed,” says Hammer, a swine technical consultant with Elanco Animal Health who’s been focused on swine for nearly four decades. “The clinical expression is quite a bit different than it was many years ago in farrow-to-finish farms. Because of this, it can go unrecognized for periods of time in producers’ herds.”
Diarrhea correlates with loss of nutrient absorption and can impact average daily gain and feed efficiency. Knowing how to identify it and how to eliminate it are key steps to keep your herd profitable.
How to Recognize Modern Symptoms of Swine Dysentery
Swine dysentery is caused by Brachyspira hyodysenteriae. These bacteria result in frank blood in the stool – fresh blood that you can clearly see, Hammer says.
Knowing the grades of swine diarrhea is critical for effective communication and early disease detection. Hammer explains that there are three grades of swine diarrhea. The classic key indicator of swine dysentery is progression toward stool containing clear gelatinous mucus and bright red, frank blood, paired with a distinctively foul odor.
- Grade 1: Soft, wet cement consistency
- Grade 2: Watery with mucus
- Grade 3: Watery with mucus, possibly with blood or with blood and mucus
“Research has shown that in three-site production, the percentage of time that we see an actual bloody scour is only 3% to 5% of the time,” he says. “Most of the time it’s a very sticky, loose diarrhea that can impact anywhere from 50% to 100% of the pigs in a barn.”
Clinical signs alone are only enough for a presumptive diagnosis. Sows often don’t show clinical signs. Even when pigs have it, they don’t look like they are suffering that bad until the disease progresses, Hammer says. However, if left untreated, it will cause runt pigs and pigs will start to die.
Eliminating Swine Dysentery
Swine dysentery is difficult to eliminate. Medical elimination requires appropriate medication, cleaning and sanitation under the direction of your herd veterinarian, Hammer says. If you have pervasive or highly prevalent diarrhea in your herd, he urges producers to get a proper diagnosis.
“When you have diarrhea in your finishing pigs, people think of ileitis caused by Lawsonia, but rarely do they consider swine dysentery,” he says. “The same drugs achieve clinical resolution for both, but if you treat a herd for what you think is ileitis, and six weeks later they’re scouring the same type of scour, get an anaerobic culture done immediately.”
The Danger of Misdiagnosis: Distinguishing Dysentery from Ileitis and Salmonella
Although cultures take more time to get back, Hammer says it’s a more definitive test. When dealing with diarrhea, knowing what you are dealing with is critical. He believes that’s why swine dysentery is making a larger comeback now – because it’s been misdiagnosed often.
“The same drugs treat both diseases. When you think you’ve fixed the ‘problem,’ and it comes back, you’ve inadvertently been tracking it around,” Hammer says. “Swine dysentery does not create the same immunity that ileitis does.”
In about 80% of the cases of finishing pig diarrhea that he treats, the results come back as Salmonella, ileitis or swine dysentery. Drugs available to treat various forms of diarrhea are effective in covering up swine dysentery, but he wants people to be aware of what they are dealing with.
“I had one producer that kept saying his herd had Salmonella,” Hammer says. “We took samples, did the anaerobic cultures and discovered it was dysentery. Get the right diagnosis, especially if you have persistent diarrhea.”
