We vaccinate all of our calves at about 4 months and again at about 6 months with Cattle 4, Cattle 7, and Pasteurella, etc. Also get invermectin injection for de-worming. Heifers get their bangs test & vaccination by Vet around 6-9 months old. All cattle get spring & fall injectible ivermectin for de-worming and an annual booster with Cattle 4 & 7. Bulls get Stay Bred VL5 before breeding season. If we have a bull out on lease, he gets de-wormed and Stay Bred VL5 upon return.
And, when flies are a problem, we spray with Permectrin II as frequently as needed...bulls seem the most vulnerable to flies. Others it varies.