Bovine Respiratory Disease (BRD) is a major problem for cattle and it continues to cause serious economic losses. Pneumonia is its most serious form. BRD causes increased death losses, higher medication and labor costs, and lost production. It occurs most commonly within a few weeks of weaning and is especially troublesome then. BRD is more serious in calves which are shipped long distances right after weaning and is often referred to as shipping fever.
Bagley, Clell; Snyder, Donald; and Matthews, Nyle, "Vaccinating to Prevent Pneumonia" (1997). All Current Publications. Paper 414.