Changing weather conditions can create respiratory challenges for calves. Cooling temperatures in fall and big temperature swings between day and night can lead to stress and wear on calves’ immune systems.

“Cooler weather may require closing windows and doors to calf housing,” says Greg Edwards, DVM, dairy technical services, Pfizer Animal Health. “That can create an environment with poor ventilation, minimized air exchange and, potentially, a buildup of bovine respiratory disease-causing pathogens, which calves can pick up easily.”


BRSV spreads as easily as the common cold

One of the causes of bovine respiratory disease (BRD) is bovine respiratory syncytial virus (BRSV). An omnipresent pathogen, BRSV is as common to calves as cold germs are to humans — it affects up to 70 percent of dairies.1

“It’s just as easy for calves to acquire BRSV from infected pen mates or surfaces on the farm as it is for humans to pick up cold germs on shopping carts,” Edwards says.

Calves have a greater chance of developing a respiratory infection during high-stress times, such as weaning or moving to group housing. While respiratory diseases appear most often during such events, calves may be exposed to the virus earlier in life. Research shows that not only are calves affected with BRD in the first few months of life more likely to die, but those that survive grow more slowly, calve later and produce less milk in at least their first lactation.2


Vaccinate to help prevent BRSV

“Vaccinating newborn calves using an intranasal vaccine (such as INFORCE 3) helps prime their immune systems to help protect their lungs and lives,” Edwards says.

A trial tested young calves’ response to INFORCE 3 intranasal respiratory vaccine, and results showed that INFORCE 3 helps override BRSV maternal antibodies present in colostrum. Calves vaccinated with INFORCE 3 had a 57 percent reduction in lung lesions and 70% less mortality than the control group of calves, following a challenge with BRSV.3


Jump-start their immunity

Help boost calves’ immunity by following these tips on nutrition, calf care and intranasal vaccination:

  • Feed calves high-quality colostrum within the first few hours of life.
  • Give an initial intranasal vaccination within the first 24 hours to help build strong immunity against bovine rhinotracheitis (IBR), parainfluenza 3 (PI3) and BRSV.
  • Provide pre-weaned calves enough calories and protein to more than double birth weight by 60 days of age through milk replacer or pasteurized whole milk and a balanced starter.
  • Feed calves based on individual size and weight, and adjust feeding based on outside climate.
  • Be consistent with rations and feed at the same time each day. If changes are necessary in diet or feeding time, do so gradually.
  • Revaccinate calves before moving to group housing.
  • Provide ample space for resting and for feed bunks in group environments.
  • Maintain proper air exchange to keep fresh air coming in while minimizing growth of airborne pathogens and eliminate harmful odors.

Work with your veterinarian to evaluate calf health and management on your dairy operation.


1 Steven T, Grubbs ST, Kania SA, Potgieter LND. Prevalence of ovine and bovine respiratory syncytial virus infections in cattle determined with a synthetic peptide-based immunoassay. J Vet Diagn Invest 2001;13(2):128-132.

2 Van Der Fels-Klerx HJ, Martin SW, Nielen M, Huirne RBM. Effects on productivity and risk factors of bovine respiratory disease in dairy heifers: a review for the Netherlands. Netherlands Journal of Agricultural Science 2002;50(1):27-45.

3 Data on file, Study Report No. 3131R-60-11-857, Pfizer Inc.