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Dairy Heifer Respiratory Health Tied to Future Milk Production

dairy heifer in milking string

A single case of pneumonia in a heifer calf can affect milk production when she enters the milking string. Mark van der List, DVM, Boehringer Ingelheim, describes ways producers can help boost calf immunity against respiratory disease-causing pathogens.   

A recent study found that heifers infected with bovine respiratory disease (BRD) had their first calf 12 days later and produced an average of 2.4 fewer pounds of milk per day than heifers that were not diagnosed with BRD.1

“A single case of diagnosed pneumonia in a heifer calf can affect milk production when she enters the milking string,” said Mark van der List, DVM, Boehringer Ingelheim. “When there are multiple instances of disease, growth rates and reproductive efficiencies are often impacted, and there’s an increased likelihood that she will end up being culled.”1

Heifer rearing is a major expense for the U.S. dairy industry, accounting for 15 to 20% of the total cost of milk production.2 Respiratory disease significantly increases that cost, at up to $16.35 per preweaned calf and $2.22 for a weaned calf.3

It’s critical to protect dairy calves from BRD to minimize any long-term effects and to maximize the return on investment in replacement heifers.

Preventing the problem

A well-planned calf-starter program helps build a solid foundation for the future performance of a calf. The following management practices reduce exposure to disease-causing pathogens, bolster immunity and contribute to the calf’s health, well-being and success in the herd: 

  • Minimize exposure to adult cattle; a calf should be removed from the mother within an hour of calving 

  • Supply high-quality colostrum within four to six hours after birth 

  • Ensure calves avoid any nose-to-nose contact with other cattle prior to weaning 

  • House animals in clean, dry and well-ventilated pens 

  • Ensure proper nutrition, including constant access to fresh, clean water 

  • Vaccinate calves against respiratory, digestive and other disease challenges 

 

Detecting disease early 

Even with a great calf-starter program, some calves will still be affected with BRD, and recognizing the disease early on is often the key to minimizing damage. 

“By catching a calf starting to exhibit signs of BRD in a timely manner and administering an appropriate treatment, you’re giving them a better chance at responding favorably to the treatment,” explained Dr. van der List. 

An elevated temperature is a clinical sign of BRD, but body temperature can fluctuate, so it may not be a reliable indicator of disease. Other clinical signs that can help identify respiratory disease include reduced appetite, coughing, nasal discharge, depression, eye discharge, droopy ear and head tilt. Once a calf is displaying one or more signs of disease, it is time for the caretaker to evaluate whether or not it needs an antibiotic. Consult with the herd veterinarian to apply protocols for the detection and treatment of BRD.

Protecting productivity with preweaning vaccinations

While early diagnosis and treatment can help prevent the calf from developing a more severe or chronic respiratory disease, prevention yields the greatest benefits for calf welfare and productivity. 

Weaning is the highest-risk time period for BRD. It involves a stressful change in diet and increased risk for pathogen exposure due to commingling of animals that may have been previously separated. Antibodies in the colostrum that calves received shortly after birth have also declined dramatically during this time, and are no longer providing adequate protection against disease.4

Dr. van der List encourages producers to consider administering a modified-live virus vaccine prior to weaning to increase immunity against common respiratory pathogens. “The time frame for vaccinating calves will vary from farm to farm, but ideally, the calf will build up enough immunity from the vaccine by the time it starts facing the challenges associated with weaning.” 

Early vaccination can also help ensure calves have a more rapid immune response to the pathogens that contribute to BRD, including bovine viral diarrhea virus (BVDV). 

“BVDV Type 1b has recently been identified as the most common subtype of BVDV found in persistently infected calves, but not all respiratory vaccines are labeled to protect against this threat,” noted Dr. van der List. “Be sure to choose a vaccine that offers solid protection against the primary viruses and bacteria that contribute to BRD, including BVDV Type 1b.” 

Note, antibodies absorbed from colostrum can interfere with the development of immunity from vaccines for several months after birth, so it’s also important to administer a vaccine proven to develop immunity in calves even in the presence of colostral antibodies.5

Be sure to consult a local veterinarian to tailor calf management practices to protect against respiratory disease and prevent future production losses.   

 

References: 

1 Jordan E, Bilby T, Lager K. Lasting effects of BRD in calves. Texas A&M Agrilife Extension. 2012. Available at: https://agrilifecdn.tamu.edu/texasdairymatters/files/2010/07/10-12-Lasting-Effects-of-BRD-in-Calves_EJordan_FINAL-Updated-01-17-1.pdf. Accessed November 11, 2019.

2 Heinrichs J, Tozer P, Gabler M, Schriefer T. Heifer economics. Penn State Extension. 2016. Available at: https://extension.psu.edu/heifer-economics. Accessed August 13, 2019.

3 Gorden PJ, Plummer P. Control, management and prevention of bovine respiratory disease in dairy calves and cows. Vet Clin North Am Food Anim Pract 2010;26(2):243–259. 

4 Epperson WB. Control of bovine respiratory disease (BRD or pneumonia). Ohio State University Extension. 2011. Accessed at: https://dairy.osu.edu/newsletter/buckeye-dairy-news/volume-6-issue-7/control-bovine-respiratory-disease-brd-or-pneumonia

5 Zimmerman AD, Boots RE, Valli JL, et al. Evaluation of protection against virulent bovine viral diarrhea virus type 2 in calves that had maternal antibodies and were vaccinated with a modified-live vaccine. J Am Vet Med Assoc 2006;228:1757–61.