As New World screwworm (NWS) continues to make news headlines, it’s important to be aware of your herd’s risk level and be prepared to implement additional monitoring and biosecurity measures if there is an infestation in your area.
“It will be critical for producers to strike a balance between animal health management programs and NWS risk,” says Dr. John Pollreisz, beef technical services veterinarian with Zoetis.
He says that geographical location and time of year are going to be the two biggest factors in determining herd risk levels.
“While Texas is the state that is mentioned most frequently, cattle producers in any state bordering Mexico should be aware,” he says. “In addition, Florida cattlemen should also be diligent. The last NWS infestation in the United States was in Key deer in the Florida Keys in 2016.”
The highest-risk population is newborn calves, as their navels are easily infested by NWS flies. “In South America where NWS is endemic, studies showed 48%–57% of untreated calves suffered navel strikes,” he says.1
At branding, there are many actions that can put calves at risk, such as castration, dehorning, ear tagging, and even a needle injection site. Something as small as a tick bite can be an attractant for NWS flies,” he says.
So how can producers strike a balance between animal health and NWS risk?
“We don’t want to ignore vaccinations and other health interventions entirely, because we still need to protect cattle from costly challenges, like bovine respiratory disease, as well as internal parasites,” Pollreisz says. “Any cattle producer in close geographical location to a screwworm incident should work closely with their herd veterinarian to determine risk level and potential adjustments to management practices.”
This may mean postponing health events like branding until officials have deployed sterile fly pupa in that area, and stepping up monitoring of the herd and surrounding wildlife.
Pollreisz recommends the following monitoring tips:
- Watch for wildlife that are acting abnormally. Infected wildlife may be agitated and shake their head. As the infection gets worse, they become lethargic and depressed. Remember: All warm-blooded livestock and animals are at risk, which includes horses, sheep, goats, dogs, cats and wildlife like deer and feral hogs.
- Utilize your sense of smell. An intense smell of decay is often the first indication, so you will want to investigate to find the source of the odor.
- Consider new ways to observe animals. Drones are an option we may not have had before and are already being used in many agriculture and livestock operations.
- If you hear of an NWS incident in your area, monitor credible sources and increase your observations of livestock. Reach out to your herd veterinarian with concerns.
Visit ZoetisUS.com/NewWorldscrewworm for more information on diagnosis, prevention and treatment.
About Zoetis
Zoetis is the world’s leading animal health company, driven by a singular purpose: to nurture our world and humankind by advancing care for animals. With a legacy of nearly 75 years, Zoetis continues to pioneer ways to predict, prevent, detect, and treat animal illness, supporting veterinarians, livestock producers, and pet owners in over 100 countries. We integrate deep scientific expertise, data-driven R&D, advanced manufacturing, and commercial excellence to deliver meaningful innovation across medicines, vaccines, diagnostics, biopharmaceuticals, and digital solutions. Guided by our vision to be the most trusted and valued animal health company, Zoetis is committed to setting new standards for the future of animal care through innovation, customer obsession, and purpose-driven colleagues. To learn more, visit Zoetis.com.
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