Calf in pen

Prevent Winter Respiratory Disease in Calves

Livestock | November 2025

Written by:

Jennifer Ryan has been writing about veterinary topics for nearly 20 years. She has a master’s degree in journalism, a bachelor’s degree in agricultural communications and decades of experience caring for both livestock and pets.

Help protect high-value calves by preparing for temperature swings.

Cattle producers were anticipating a warmer fall and continued high prices. This combination may give operations a longer window for protecting animals against respiratory disease – and a greater return on investment for doing it well.

“The fall is what I like to call ‘sick calf month,’” joked Jody Wade, DVM, senior professional services veterinarian, cattle, at Boehringer Ingelheim. “Starting in October, we can see temperature swings from 85 degrees in the daytime to 55 degrees at night. That is hard on calves. Once weaning starts, everything in their life is hard anyways.”

Jody Wade headshot
Jody Wade, DVM, Senior Professional Services Veterinarian, Boehringer Ingelheim

These combined stressors can result in a negative energy balance, which opens the door for compromised immune function. All this occurs at the time calves are transported, comingled and introduced to new disease challenges. Rainfall or snow in the fall can exacerbate the issue as calves struggle to maintain a normal body temperature, Wade explained.

“For every degree they lose in body temperature, they have to steal it from somewhere else,” he said.

Top 3 tips for maintaining health

With today’s market prices, it pays for producers to protect their investment. Wade’s top tips are to:

1. Dial in nutrition. Don’t skimp on a high-quality ration, especially during “sick calf season.” This is the foundation for the energy needed to fuel the immune system as well as growth.

2. Monitor calves closely. Most experienced pen riders can spot a lethargic calf, but Wade recommended producers to look for animals backing off the bunk, too. Reduced feed intake is an early sign of disease. The sooner producers treat calves, the quicker animals will respond.

3. Have broad-spectrum treatment ready. Outline antibiotic options with a veterinarian and have products on hand. After treatment, monitor calves to ensure they get back to eating and drinking.

“I usually say go to the big guns right away,” he advised. “Antibiotics with broad-spectrum coverage are really a godsend. Watch them after treatment. Calves are the first ones to drink out of mudhole, and they can pick up disease there, too. Make sure they have access to good, fresh water.”

The bacteria Histophilus somni and Mannheimia haemolytica have been on the rise the past two years, and the bacteria are major contributors to bovine respiratory disease (BRD), Wade noted.

A report from the Iowa State University Veterinary Diagnostic Laboratory showed H. somni was identified in 25 percent of BRD isolates from 2013 to 2015. Another report showed that 6.1 percent of cattle tested positive for H. somni on arrival, before any antibiotic treatment.3

“Because prices are so high, producers are tempted to pull calves straight off the cows and send them to market where they are exposed to pathogens in a stocker environment,” Wade explained. “I recently went to a sale barn and probably 50 percent of the calves were not preconditioned.”

A complete preconditioning program includes feed bunk training, vaccinations and deworming to ensure calf health is primed to fight off pathogens.

Farmer bottle feeding calf

Buyer beware and prepared

Taking extra care to protect calves can help minimize death losses and maintain gains. Wade advised stocker and backgrounder operations to keep calves quarantined until vaccinations kick in. Then, pull and treat any calves that look sick to get ahead of illness.

“When you buy calves that aren’t preconditioned, you’re taking the risk of higher morbidity and mortality,” he said. “Really be in those calves, checking for illness. This is the time we can expect to see illness, and it may be more expensive this year than any other recent time.”

 

1 Magstadt DR, Schuler AM, et al. Treatment history and antimicrobial susceptibility results for Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni isolates from bovine respiratory disease cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2013 to 2015. J. Vet. Diagn. Invest. 2018 Jan;30(1):99-104.

2 UNL Diagnostic Center News. Spring 2013. Doster and Seelmeyer.

3 Lamm, C.G. et al. J. Vet. Diag. Invest. 24(2): 277-282.

4 Histophilosis—Generalized Conditions. (n.d.). Merck Veterinary Manual. Retrieved October 12, 2025, from www.merckvetmanual.com/generalized-conditions/histophilosis/histophilosis.

5 Bacterial Pneumonia in Cattle with Bovine Respiratory Disease Complex—Respiratory System. (n.d.). Merck Veterinary Manual. Retrieved October 12, 2025, from www.merckvetmanual.com/respiratory-system/bovine-respiratory-disease-complex/bacterial-pneumonia-in-cattle-with-bovine-respiratory-disease-complex.

Key Points:

  • Recently weaned calves are at a higher risk of infection and death from Histophilus somni than are previously weaned older calves, yearlings or mature animals. 4
  • H. somni infection can be mistaken for bloat. 4
  • Mannheimia haemolytica serotype 1 is the bacterial pathogen most frequently isolated from the lungs of recently weaned feedlot cattle with BRD. 5
  • After stress or viral infection, the replication rate of M. haemolytica in the upper respiratory tract increases rapidly, as does the likelihood of culturing the bacteria. 5

 

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istockphoto.com/Ilja Enger-Tsizikov

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