Think about it. After you've been on the road or stressed out, a good day of rest bolsters your spirits and health reserve. The same is true for feeder calves.
For every hour animals spend in transport, give them at least that much time after they arrive before you start vaccinating, counsels Dr. Mitch Blanding, veterinarian for Pfizer Animal Health. This allows them a chance to rest before the additional stress of processing. That way, vaccines have a better chance of bolstering immunity.
But as any cattleman with a few years experience knows, animal immune systems may already be compromised. Respiratory diseases can take their toll, especially if you're starting with high-risk calves that are lightweight, of unknown origin or have simply traveled many miles to get to you.
Depressed immunity may be a function of immaturity and risk factors such as nutritional and trace mineral deficiency or other stressful events associated with weaning, heavy commingling and shipping.
A sound on-arrival program will include vaccinating the calves against disease before they get sick. "We first try to intervene with those animals that have a competent immune system and are capable of responding to a vaccine," notes Blanding.
"In high-risk cattle, it wouldn't be unusual for some animals to not respond to the initial vaccination," he adds. "Many operations may revaccinate these animals after initial processing in hopes of starting an immune process in more of the animals and enhancing the group's overall immunity level."