Submitted to: International Journal of Applied Research in Veterinary Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2011
Publication Date: 5/18/2011
Citation: Li, A.Y., Ross, D., Perez De Leon, A.A. 2011. Evaluation of the VetCap® treatment method for horn fly control in cattle. International Journal of Applied Research in Veterinary Medicine. 9(2):198-203.
Interpretive Summary: The horn fly, Haematobia irritans irritans (L.), is an economically damaging parasite of cattle in several parts of the world. Annual economic losses ascribed to horn fly parasitism in the U.S. alone, are estimated to be $876 million dollars. Despite the evolution of resistance to chemicals able to kill horn flies, the use of insecticides remains an important part of integrated horn fly control programs. Various approaches have been taken to apply insecticides to cattle topically and systemically for horn fly control since the late 1940s. Many insecticide treatment methods require repeated animal handling, which may cause stress in cattle and injury to cattle handlers in addition to added labor costs. VetCap® is an innovative remote insecticide application method developed by SmartVet Pty Ltd (Brisbane, Australia). A field trial was conducted to evaluate the horn fly efficacy, of an encapsulated commercial insecticide (CyLence®) formulation that was applied to cattle using the VetCap® treatment method. One (CyLence®) pour-on treatment group and one untreated group were also included in the study for comparison. Horn fly counts were made two days before and four days after insecticide treatment in all groups, and subsequently on a weekly basis for 5 weeks. Both treatment methods provided significant control of horn flies for about three weeks. A higher level of control was achieved with the pour-on treatment, which was largely due to smaller animal size and lower pre-treatment fly load on animals. Optimization of the VetCap® treatment method may offer the opportunity to enhance efficiencies through diverse veterinary applications in livestock production systems.
Technical Abstract: A field study was conducted to evaluate the efficacy of the VetCap® treatment method, (SmartVet Pty Ltd, Brisbane, Australia) to control horn flies infesting cattle. The VetCap® delivery system consists of a pressure (liquid CO2) driven launcher and an encapsulated insecticide (CyLence®) formulation (10 ml CyLence® gel capsules). Three groups of cattle on three adjacent pastures were used, including (1) animals treated with 10 ml CyLence® pour-on formulation, (2) animals treated with VetCap® treatment method (10 ml CyLence® gel capsule), and (3) the untreated animals. Horn fly counts were conducted at two days prior to treatment, and at 4, 11, 18, 25, 32, and 39 days post treatment. Mean fly numbers per side of animal of all three groups at each sampling date were obtained, and percent controls of each treatment method were generated by comparing them to: (1) the untreated control group, and (2) the pre-treatment fly count within the treatment group. Both treatment methods provided significant control of horn flies for about three weeks. A higher level of control was achieved with the Pour-on treatment, which was largely due to smaller animal size and lower pre-treatment fly load on animals. The VetCap® method is amenable to other applications for the remote treatment of domestic animals and wildlife species. Testing the VetCap® method’s utility to treat cattle, horses, white-tailed deer, and other exotic ungulate wildlife species found to be infested with cattle fever ticks in the US is warranted.