Investigating Multimodal Parasite Control 

Julia Herman, DVM, MS Beef Cattle Specialist Veterinarian, NCBA, a contractor to the Beef Checkoff | June 10, 2024


Cattle producers are creative folks. Talk to producers in different states, even different parts of the same county, and you’ll get multiple ways of solving the same problem. Parasite control definitely fits in this category, along with fence fixing, facility design, nutrition programs, and many others. What technique works for humid areas in the southeast U.S. is not the same that may work in the western states. Multimodal approaches to parasite control challenges producers and their resource teams to use more than one technique to reduce parasite populations and thereby the potential negative consequences on the herd. For a parasite control program specifically, working with your local veterinarian, extension agent, industry representatives, or local entomologists will help tailor a strategy to the specific operation. This resource team can help in understanding the specific insects in your region, their effects on animal health, and utilizing multiple methods of prevention and treatment is important to protecting your herd and minimizing negative consequences. 


Knowing what parasites your herd is dealing with is the first step to building a plan. Every ranch has flies – but which ones do you have? Seeing where the flies are on the cattle or environment is key. Horn flies tend to congregate on the back and shoulders of cattle or move to their underbelly during the heat of the day, especially with cattle grazing on pastures and rangeland. Face flies are found near the eyes and nose of cattle which can cause irritation and damage to the eye itself and surrounding tissues. Stable flies are commonly found where hay and manure are mixed, from pasture to backgrounding or feedyard operations. Ticks are also an important parasite to consider since they can carry diseases themselves and cause hide damage, blood loss, and reduced weight gain. 

Internal parasites, such as worms, can be challenging to diagnose without completing routine surveillance of fecal samples. This strategy can be used to determine if deworming is needed for an individual animal or herd. Fecal Egg Count Reduction Tests (FECRT) can be run as a screening test with the help of your veterinarian and are designed to measure the efficacy of the anthelmintic treatment. 

Because parasite management varies by region with differences in climate, environmental conditions, host susceptibility, and farm/ranch management practices, having a parasite control program is critical. With proper nutrition and grazing management plans, many parasites can be controlled through environmental management. Anthelmintic resistance, where internal and external parasites have developed resistance to the animal health products and dewormers readily available for parasite control, is not regional. Multimodal approaches to parasite control, if conducted appropriately, can keep products effective for longer and reduce promotion of resistance. 

Because of anthelmintic resistance, treatment protocols have become more complex than giving a single product and necessitate veterinary consultation. As discussed in the Beef Checkoff-funded Beef Quality Assurance (BQA) Program, proper dosing to bodyweight of the animal plays a role in effectiveness of the medication. Applying the product as the label, including dosage, route of administration, and correct parasites, are also important to reducing misuse and resistance development. Do not forget that many topical and injectable parasite treatments have withdrawal periods to adhere to, so read the label and keep accurate records of when products are used. 

Preventive practices, like those found in the BQA program, are paramount for the management of ectoparasites in conventional and organic operations. Providing adequate nutrition to develop a strong immune system, managing pastures and working areas properly, optimizing sanitation practices to minimize predisposing conditions for parasite breeding grounds, and reducing stress all contribute to a successful response to integrated insect management. For further guidelines on herd health and animal product management, check out the BQA Field Guide in the resources section at bqa.org.     

This article was originally published in the July 2023 issue of NCBA National Cattlemen newsletter.