In the Arkansas River Valley, Cy Shurtleff, DVM at Morrilton Veterinary Clinic in Morrilton, Arkansas, has identified liver flukes as the culprit in poor-doing cattle more often in recent years.
But effective liver fluke (Fasciola hepatica) control can often be challenging: Flukicides only kill adults.
Fortunately, there is an opportunity to catch the adult flukes before they begin laying eggs. Unfortunately, this window of opportunity is small. It takes 10-12 weeks from the time fluke larvae are ingested until they become adults. New larvae availability stops for a few months as snails go dormant into the mud. But then, the fluke cycle and transmission will start again.
When and where:
For effective fluke control, you need to time treatment when snails are dormant in the mud and adults are most prevalent — thereby, breaking the fluke life cycle. This is primarily summer, mostly August and September, for producers in Gulf Coast states, and, for producers in the Pacific Northwest region, treatment should occur three months after the wet areas dry up. This is because it takes three months for the immature flukes to mature in the animal. This visual outlines timing considerations for the Gulf Coast region.
Liver flukes tend to be more prevalent in these regions because of geography. Mild and wet spring and fall weather brings larger amounts of water and snail populations. The common liver fluke is a parasite that requires water and a snail host to complete its life cycle.
“We’ve been running fluke finder tests because we’ve seen cattle that do not seem to be responding to dewormers as well,” Dr. Shurtleff said. “We realize flukes are out there because we are in an area that’s wet most of the year, and fluke finder is an easy test we can run in-house. It’s only a 10-minute test to run, so you can do several fairly easily.”
In addition to slower response to treatments, liver flukes can cause:
• Lack of appetite
• Pain in cattle in early infection stage
• Slow, steady weight loss
If you’re in one of these regions, or if you have cattle grazing coastal areas or river bottom pastures, work with your veterinarian to learn if flukes might be an issue and to develop an effective control program. If you’ve had a problem identified in the past, it’s important to continue control measures in subsequent years as conditions may continue to support the fluke life cycle.
You have a window of opportunity to break the fluke life cycle with a product that is labeled to help remove and control adult liver flukes at the right time. If you use a product that helps control liver flukes in addition to other major parasitic worms you need to control, then you won’t have to add another product into your rotation.
Flukes are one challenge, but they aren’t the only challenge you might have.
“In our area, we have about 10 months of possible parasite transmission,” Dr. Shurtleff said. “A lot of years, we do not get our first heavy frost until late November or early December, so cattle and young calves are starting to graze at that time and they're picking up parasites. Parasite control is the cornerstone of our herd health program at our clinic. If animals are being challenged by parasites, even the greatest vaccine program in the world will fail.”
For more information and about solutions from Zoetis, visit GetLessParasites.com.
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