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ARS Home » Plains Area » Kerrville, Texas » Knipling-Bushland U.S. Livestock Insects Research Laboratory » LAPRU » Research » Research Project #437280

Research Project: Year 2 CFTEP Funding-Continuation of Field Studies Using 1% Doramectin Product and Bm86-Based Vaccine Against Cattle Fever Ticks

Location: Livestock Arthropod Pests Research

Project Number: 3094-32000-042-043-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 15, 2019
End Date: Apr 30, 2022

Objective:
Determine if a double dose of injectable doramectin will protect cattle against CFT infestation beyond 28 days and also determine the efficacy of combined treatments of doramectin + Bm86 vaccine and eprinomectin+ Bm86 for controlling CFT on cattle in the field. A segment is being added which we anticipate will offer CFT researchers and the CFTEP new information on seasonal climate variation among CFT microhabitats and in pastures utilized by grazing cattle, which will expand the understanding of seasonal weather patterns on CFT larval habitats, pasture usage by grazing cattle, and CFT dispersal.

Approach:
The original Approach is modified for two field studies to be be conducted to evaluate the use of macrocyclic lactones for controlling CFT on cattle. The first field study will evaluate the level of doramectin in the plasma of cattle treated with a double label dose of injectable doramectin. Blood samples will be taken from control and treated animals over time and will analyzed to determine if plasma levels of doramectin reach concentrations that are adequate for extended CFT control. The second field study will determine the efficacy and persistence of CFT treatments that combine macrocyclic lactone acaricide treatments with the Bm86 vaccine. Cattle infested with CFT will be treated per a set schedule with either Bm86 only, 1% Doramectin + Bm86, or 5% Eprinomectin + Bm86. Routine tick counts will be conducted as well as blood draws over time. Engorged female CFT will be held and assessed for fecundity. Blood samples will be analyzed to determine the levels of doramectin and eprinomectin over time as well as antibody response to the Bm86 vaccine via ELISA. The detailed approach methods are incorporated into the full statement of work for the cooperative agreement.