Breed composition does not influence the performance of Holstein-Gyr crossbred as oocyte donors for OPU/IVP.

Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein () and Gyr () breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the world's largest user of embryo production (IVP) in bovine, and the use of this technique is increasing in dairy systems.