With the recent detection of New World Screwworm (NWS), the U.S. livestock industry and animal health agencies must be aggressive in inspecting herds for signs of parasitic infestation and tracking the spread of this renewed threat. Key action items for ranchers to take when protecting their herds from this parasite are outlined below.
Ensure that all ranch employees are familiar with the NWS life cycle and signs of infestation. Female NWS flies lay eggs in existing wounds or around mucus membranes. Infested wounds exhibit bloody discharge, swelling, and the odor of rotting flesh. Infested animals can display discomfort, impaired gait, restlessness, lethargy, or separate themselves from the herd.
Herds should be inspected daily. Early detection and treatment of NWS infestation can significantly decrease the fly’s ability to gain a foothold in an area and improve survivability from wounds.
Ensure that you are familiar with the USDA-APHIS NWS Response Playbook that outlines how animal health officials will implement NWS surveillance, containment zones, and animal movement restrictions. Ranchbot distilled this playbook into Key Points for Cattle Ranchers.
Ensure that your ranch has an established veterinarian-client-patient relationship (VCPR) with a large animal veterinarian that is familiar with your operation.
Local veterinarians or State Animal Health Officials are the first point of contact for reporting a suspected NWS case and will coordinate positive identification of suspected NWS presence with USDA-APHIS officials. Timely reporting of suspected NWS cases is vital for the response to this animal health threat.
Isolate suspected animal where they are on the ranch to prevent the spread of NWS within the herd. If possible, use nearby or portable corrals to isolate them rather than transporting them to a different part of the ranch for inspection. Coordinate further animal movements with animal health officials.
Physically checking water infrastructure diverts labor from inspecting cattle for fresh wounds that lead to NWS infestation.
Adopt remote monitoring solutions that improve strategic decision making, increase labor availability for checking cattle, and reduce unnecessary human movement between pastures.
Implement a multi-faceted external parasite control plan with consultation from a veterinarian. Components of this plan can include pour-on insecticides, fly tags, dust bags, and feed through fly control.
Consult veterinarians on NWS treatment options based on products that are approved for treatment of NWS. Be sure to follow product withdrawal guidelines to ensure safety of the food supply.
The latest USDA-APHIS updates on the NWS situation can be found at screwworm.gov.