I am buying light weight calves,usually under 500#.  If there is no mention of shots at the sale, I drop by the vet after loading.  My vet is next to the sale barn.  Run them through for shots, dehorn if needed, and casterate if needed.  Take them home and put them in corral for 10-14 days feeding grass hay and about 2# grain per calf and lick tub mineral.  Turn them out for grazing after that or into winter feeding area depending on time of year.  They get about 3# of grain everyday till sold at about 700#.