Vascular perfusion and the volume of the preovulatory follicle are affected by the temperament of Nellore cows

•The blood flow in the preovulatory follicle wall is lower in the excitable cows.•Excitable cows have smaller preovulatory follicle volume.•Temperament affects the morphological characteristics of the preovulatory follicle.•The P4/CL volume ratio was higher in the excitable cows.•The volume of the corpus luteum is smaller in excitable cows.