The process of weaning calves is the most significant source of bovine respiratory disease (BRD) outbreaks. Understanding why weaning calves contributes to breakouts is important, as are the steps to consider during the process to reduce the risk of BRD.
The calf has an immune system that is particularly impacted by environmental and feeding changes when they are between 300 and 600 pounds. They’re moving from the dam and wide open pasture into a collection of contemporary animals from different sources. That introduces new strains of bacterial and viral diseases that the calf hasn’t yet been exposed to, and it’s asking the calf to acclimate to a brand new environment of feed and water, which takes time. You put those two obstacles together and the calf’s immune system may be compromised. In addition, putting them on a truck and transporting them any given distance can cause the calf to become dehydrated and anxious. And when those scenarios combine, you may have an explosive event where the animal is highly immune-suppressed.
There are steps that can be taken to avoid BRD outbreaks prior to, throughout and post weaning. They include vaccinations prior to weaning, minimizing transportation distances and maintaining nutrition. These will be further explored in “Reduce Stress When Weaning to Reduce BRD Outbreaks – Part 2.”