Ten crossbred calves (Friesian x Egyptian native) aged between 7-9 months old were used to evaluated the effect of cattle immunization with the whole adult B. annulatus tick antigen. A soluble fraction was obtained from extensively disrupted ticks and this fraction was used to vaccinate calves with 1mg protein antigen. The vaccination protocol for five randomly selected calves involved two immunizations, the first was administered subcutaneously (Plus aluminium hydroxide adjuvant) at the beginning of the experiment and the second was given 4 weeks later. At the same time, calves of the control group were injected with phosphate buffered saline (PBS) plus adjuvant. Ticks were counted on animals and the number of eggs laid per tick was counted and hatching percentage was determined.
The vaccinated and control animals were skin tested with the antigen and calves were injected in three different sites with 50ul of 50, 100 and 200ng of the antigen. At the same time, control sites were injected with PBS saline and the diameter of the immune response sites was measured using skin caliper. Immunization of calves showed that vaccination resulted in 73% reduction in the mean tick count. At the same time, immunization reduced the oviposition of eggs in vaccinated calves and the reduction percentage in egg laying was 65%. Vaccination induced a good immunity that could protect calves during the tick season (more than 5 months) as indicated from skin hypersensitivity reaction with the tick antigen.