Cattle Biting Louse Control, 1979

Twenty new-born bull calves were purchased in late December - early January and housed in a temperature controlled calf barn at 10-13°C. Test calves were maintained in veal calf crates modified with plywood and galvanized iron sheeting to prevent contact be-tween animals or louse immigration. Calves were assigned randomly to 4 treatment groups, 5 calves each, in a completely randomized design. A single appli-cation of each treatment was applied on Feb 10. Louse populations were sampled at weekly intervals beginning two weeks prior to treatment and for 6 weeks post-treatment. Ten sites on each animal were sampled; two were narrow strips along the dorsal midline, one between the shoulder blades, the other just anterior to the railhead. The other sample sites were 4x4 inch areas, each defined with a template, two on each side of the withers and the rump approx-imately 10 inches down from the midline. All late instar and adult lice observed in each sample area were talleyed and a mean was calculated for the number of lice at each site within treatments. Weekly mean values were compared by analysis of varience.