Recent developments in cattle tick control have incorporated the use of recombinant Bm86 vaccines against this ectoparasite. The vaccine developed by our group (Gavac) contains an antigen expressed in Pichia pastoris, and has been successfully employed for the control of tick infestations and transmission of tick-borne diseases. Here, we examined the safety and effect of the Gavac vaccine on reproductive parameters in cattle. Toxicity tests in mice and guinea pigs demonstrated the safety of Gavac. To study the adverse effects of vaccination on reproduction, a field trial involving 9,500 animals in Cuba was conducted. The cattle at 3 farms were vaccinated while those on a fourth farm were left unvaccinated and served as the control. Following vaccination, the control of tick infestation and the transmission of babesiosis were used to demonstrate the efficacy of the vaccine. No adverse effects were observed in any of the reproductive parameters studied when comparing the data before and after vaccination with Gavac and between the vaccinated farms and the control farm. These results demonstrate that under the conditions of our study vaccination with Gavac is safe for use on cattle.