Correct Timing, Dosing Critical in Fluke Control

Small window of opportunity allows for effective control of flukes

The common liver fluke (Fasciola hepatica) is a parasite that requires water and a snail host to complete its life cycle. This highly damaging parasite is primarily located in Gulf Coast states and the Pacific Northwest, where large amounts of water and snail populations are found. For cattle producers in these areas, proper timing is critical to disrupt the fluke life cycle with a liver fluke control product.

“Producers have one opportunity to truly control flukes, when the snails are dormant in the mud and cattle are infected with mostly adult flukes,” said Mark Alley, Managing Veterinarian with Zoetis. “Products, like VALBAZEN®, are effective in the removal and control of adult liver flukes so timing is everything.”

For most fluke-infested areas this means August and September are the best time to treat cattle because hot, dry weather drives snails into dormancy, breaking the life cycle. Flukes depend on snail hosts and cattle hosts to complete their life cycle. The key is to catch adult flukes in a cattle host before the adults begin laying eggs to contaminate the environment, and the snails are dormant cutting off continued infection with immature flukes.

“Flukicides do a poor job controlling and removing immature flukes,” said Dr. Alley. “The benefit of a product like VALBAZEN, with albendazole as an active ingredient, is that you get control and removal of adult flukes, but it is also really effective at controlling Haemonchus contortus and placei, as well as Cooperia and inhibited Ostertagia ostertagi. These internal parasites can impact productivity and overall animal health.”

The amount of economic loss caused by liver flukes in cattle is not easily defined because infections aren’t uniform throughout a herd and the level of infection is not easily identified. Dr. Alley points out that flukes migrating through the liver leave animals susceptible to clostridial diseases like black leg (Clostridium novyi) and Red water disease (C. haemolyticum).

“You can see the impact of liver flukes at the feedlot with the animal’s ability to process nutrients,” said Dr. Alley. “There isn’t much you can do for them at that point because the damage is already done. Liver fluke control earlier helps performance later in life.”

Dr. Alley recommends watching for the following signs or symptoms:
• Lack of appetite
• Slower to respond to stimuli
• Show signs of pain in early infection stages
• Slow, steady weight loss

If a producer suspects a liver fluke infection, Dr. Alley says they should contact a veterinarian right away. He adds that once a fluke problem has been identified in a herd, it is important to continue control measures in subsequent years since conditions may continue to support the fluke life cycle. A well-planned strategic parasite control program can help protect cattle from challenges like liver flukes and support an overall healthier herd.

For more information about VALBAZEN or other parasite control products from Zoetis, contact your local Zoetis representative or herd veterinarian.

Cattle must not be slaughtered within 27 days after the last treatment with VALBAZEN. Do not use in female dairy cattle of breeding age. Do no administer to female cattle during the first 45 days of pregnancy or for 45 days after removal of bulls.

About Zoetis
Zoetis (zô-EH-tis) is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 60 years of experience in animal health, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in more than 100 countries. In 2015, the company generated annual revenue of $4.8 billion with approximately 9,000 employees. For more information, visit

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