The disease exposure, the presence of resistant disease strains, increased stresses, and diet restrictions applied to the calves begin immediately after leaving the farm of origin. The fall in the resistance level is primarily due to weaning, shipping, diet change and other stresses. To insure that calves are healthy and will remain healthy, all calves must be properly prepared before marketing and shipment. Proper preparation prevents the resistance level from dropping drastically, raises the level of resistance against certain diseases, and reduces certain disease challenges. In essence, with proper preparation, we keep the resistance level and disease challenge levels from intersecting.
Calves can handle stresses much easier if they are still with their mothers.
We can reduce certain disease challenges by using certain products and management techniques. We can raise the resistance to certain diseases by use of vaccines. The trick to successfully raising the resistance by use of vaccines is not only selecting the proper vaccine, but knowing how vaccines work and timing the vaccination so that the resistance level is raised before the disease challenge occurs. The two doses of vaccines should be given at least 21-28 days apart. When sending calves through a commingling market, where the disease challenge level starts up rapidly on the day the calves leave the farm, marketing should not occur until at least 30 days after the 2nd doses of vaccines are administered.