Boost Calf Immunity to Beat Summer Pneumonia

beef calf in chute

Life should be easy for preweaned calves on pasture. They have yet to deal with the stresses of weaning, transportation or commingling with cattle from other operations. So why should producers be worried about respiratory diseases such as summer pneumonia now?

  • Changing weather patterns

Several environmental factors such as weather extremes and fluctuating temperatures can cause stress. Hot, dry and dusty conditions can interfere with animals’ respiratory tract defense mechanisms, and parasite infestations can suppress their immune systems.

  • Diminishing antibodies

Maternal antibodies naturally diminish before calves’ immune systems are fully competent, leaving an open door for viruses and bacteria to invade the lungs.

  • Subtle signs surfacing

In the early stages of summer pneumonia, calves may only show subtle signs, such as lethargy, droopy ears and loss of appetite. As the infection progresses, calves can experience fevers, coughing and rapid breathing. Since it can be difficult to observe calves on pasture, producers may not realize there’s a problem until calves turn up dead.

Waiting until weaning to vaccinate could leave calves unprotected during the summer months, when they are most susceptible to summer pneumonia. In fact, studies have shown that calves impacted by a respiratory disease prior to weaning are, on average, 36 pounds lighter at weaning than their herd mates.1,2

Vaccinating calves against pneumonia before weaning with a modified-live virus vaccine is one of the best ways to help reduce stress and boost immunity for challenges they will face down the road. Every operation is unique, so I encourage producers to work closely with a veterinarian to formulate an effective vaccination program that’s tailored to their herd’s needs.



1 Snowder GD, Van Vleck LD, Cundiff LV, Bennett GL. Influence of breed, heterozygosity and disease incidence on estimates of variance components of respiratory disease in preweaned beef calves. J Animal Sci 2005;83(6):1247–1261.

2 Wittum TE and Perino LJ. Passive immune status at postpartum hour 24 and long-term health and performance of calves. Am J Vet Res 1995;56(9):1149–1154. 


©2021 Boehringer Ingelheim Animal Health USA Inc., Duluth, GA. All Rights Reserved. US-BOV-0586-2021