While liver flukes rarely result in cattle death losses, understanding their underlying impact is important for cattle health and an operation’s bottom line.
“The biggest problem with flukes is their impact on production,” says Jody Wade, DVM, Boehringer Ingelheim. Liver flukes are one of the more complex parasites in beef production.
Before setting up camp in the bile ducts of the liver, juvenile flukes cause damage in the small intestine and abdominal cavity as they travel, leaving cattle with weakened immune systems and lost growth potential.
Cattle with liver fluke infections can go months without showing clinical signs. Depending on the level of infection, cattle can experience loss of appetite, rough hair coat, decreased performance, weight loss and poor reproductive efficiency.
“The ones that really pay for it on the back end are the packers,” Wade explains. “When they start harvesting cattle and find flukes, they have to condemn those livers.”
Liver condemnations can lead to significant financial losses, particularly for feedlots and processors.
Diagnostic Testing is Key for Awareness
Wade explains diagnostic testing is needed to confirm liver fluke presence, which often goes unnoticed.
“We’re finding flukes in regions we never thought they would be,” he observes. “Unless you’re taking fecal egg counts and actually looking for liver flukes as a cow-calf operator or a stocker, you’re not going to find them.”
Diagnostic testing in regions like Kansas and Tennessee has confirmed the presence of liver flukes, challenging the misconception that liver flukes are confined to the Gulf Coast or Pacific Northwest states.
Routine testing isn’t just crucial for fluke control, it’s important for sustainable management of all internal parasites.
“Not a lot of producers are routinely testing, because it can be a time burden,” Wade explains. “But I still encourage producers to do it, because once we do, we have a really good snapshot of what is happening on the operation, which allows us to create the most strategic deworming plan.”
When producers send fecal samples for diagnostic testing, he reminds them to specify their desire for liver fluke analysis. A general diagnostic test will only look for common gastrointestinal parasites.
Liver Flukes Require Special Management
“Right now, there are only two products in the marketplace available for effective fluke management,” Wade says. “When selecting a product for liver fluke control, it’s important to look for a product that has clorsulon, or is specifically labeled for fluke coverage.”
He further explains that the available products are only effective against adult stages and do not kill juvenile flukes, which cause the most damage. But, when applied correctly, the elimination of adult flukes can disrupt the production cycle and reduce the risk of pasture reinfestation.
Understanding the life cycle of liver flukes, from egg to adult, is essential for implementing effective control measures. Unlike other internal parasites, flukes need an intermediate host to propagate. For flukes, this is a common freshwater snail.
The fluke larvae migrate to snails, where they multiply. Once they exit the snail, cattle can ingest them by grazing on infested grass or drinking infested water.
While it isn’t realistic to keep cattle away from areas that also attract freshwater snails, sustainable deworming practices like pasture rotation and refugia, the practice of only deworming high-risk animals, are also ways to help control liver flukes and other parasite populations.
“Effective fluking really comes down to timing,” Wade says. “In the southeastern part of the country, like in Louisiana, Alabama and Mississippi, September is probably the best time to deworm for those liver flukes. In the Pacific Northwest, it’s a different deal. Most parasitologists will tell you to deworm between March and May, because it’s a later liver fluke season in that region.”
Wade says education is key to closing the gap between awareness and action.
“Sometimes, knowing that liver flukes may be a problem and not acting on that knowledge can be more harmful than not knowing at all,” he summarizes.
By adopting evidence-based practices, cattle caretakers can protect their herds, improve production outcomes and reduce the hidden costs of liver flukes. If flukes have been previously found in your area, Wade recommends getting a baseline for the herd through diagnostic testing. Only then can a sustainable, strategic deworming program be built through collaboration with a herd veterinarian.
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