Dairy Cattle Fly Control with Vigilante (tm) Premix, 1986

Holstein cattle herds were fed either Vigilante premix feedthrough or Rabon (tm) oral larvicide to evaluate their efficacy against the horn, face, and house fly. Visual counts of the above flies as well as stable flies were also made. The treatment began on 15 May and the herds were separated by a minimum distance of 10 miles. Premixes were administered daily by adding them to the mineral mix concentrate prior to adding into the total ration. Herds were treated as follows: 105 cows along with 44 calves and heifers were given 3.8% Vigilante premix at a rate of 5 mg AI/100 lb body wt. (A); 130 cows and 35 heifers were given a 7.76% Rabon oral larvicide at a rate of 70 mg AI/100 lb body wt. (B); 90 cows untreated (Control). Horn flies and stable flies were evaluated on 10 animals on a bimonthly basis. Horn flies were counted on one side of the animal and stable flies were counted on the legs of the same animal. House fly counts were taken within 1 square meter grids at 10 different locations around the cow loafing area. Normal fly control procedures included sanitation, misting, and hand spraying of resmethrin or permethrins. Fresh manure was collected from 5 animals bimonthly and bioassayed using newly hatched colonized horn fly, face fly, and house fly larvae. Twenty-five larvae were placed in 50-100 g of manure sample and the larvae mortality calculated from the number of emerged adults.