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Beef Cattle Research Council - Bovine Respiratory Disease

Retrieved: March 25, 2019 - 09:05 PM

Bovine Respiratory Disease (BRD) is the most common and costly disease affecting the North American beef cattle industry. In the broadest sense, BRD refers to any disease of the upper or lower respiratory tracts. BRD is commonly associated with infections of the lungs causing pneumonia in calves that have recently been weaned or recently arrived at the feedlot (which is why it is often referred to as shipping fever). BRD is most prevalent within the first weeks of arrival to the feedlot, but it can occur later in the feeding period and is also seen in calves on pasture.

BRD accounts for 65-80% of the morbidity (sickness) and 45-75% of the mortality (deaths) in some feedlots.
 

Sections

Key Points

  • Bovine Respiratory Disease (BRD) is the most common and costly disease affecting the North American beef cattle industry
  • It is often referred to as shipping fever
  • BRD is most prevalent within the first weeks of arrival to the feedlot, but it can occur later in the feeding period and is also seen in calves on pasture
  • Classical clinical signs of bacterial BRD include:
    • fever of over 40°C (>104°F)
    • difficulty breathing
    • nasal discharge
    • varying degrees of depression
    • diminished or no appetite (‘off-feed’)
    • rapid, shallow breathing
    • coughing
  • Risk factors
    • Environmental factors such as transport, adverse weather, co-mingling, stressful events (ie. dehorning, castration, weaning, auction)
  • Prevention
    • Precondition calves before marketing
    • After arrival at the feedlot, provide a vaccination and general good animal husbandry
  • Treatment
    • It is best to work with your veterinarian for the appropriate medication and dosage
    • Common causes of treatment failure include;
      • Pathology of the lesion too far advanced
      • Wrong diagnosis
      • Simultaneous disease process (e.g.: Overt IBR, Post calving metritis)
      • Inadequate dosage
      • Overuse or inappropriate use of Ancillary Pharmaceutics

Causes

BRD is a complex multi-factorial diseasewhich means that a number of factors must interact to cause the disease. For example, researchers can recover the bacteria and viruses responsible for BRD from the nasal passages of healthy cattle. However, other factors such as the stress from transport, mixing, and weather are needed in order for BRD to develop. There are 3 main categories of factors associated with all diseases, and BRD in particular: 

Host factors, which refers to the characteristics of an animal that make it more prone to the disease, such as: age, immune status, prior exposure to the pathogens, genetics, etc. environmental factors such as transport, commingling, temperature fluctuations, crowding, ventilation, auction-sourced, etc.  

Infectious agents or pathogens that are necessary for causing the disease. These can broadly be categorized as viruses, bacteria and parasites: Viruses, including: bovine herpes virus (IBR); bovine parainfluenza virus (PI-3); bovine respiratory syncytial virus (BRSV); bovine viral diarrhea virus (BVD), and bovine coronavirus (BCV). 

  • Bacteria, including Mannheimia haemolytica, Pasteurella multocidaHistophilus somni and Mycoplasma spp. 
  • Parasites, including lungworm 
This interview with veterinarian Dr. Steve Hendrick by RealAgriculture.com explains how to recognize and deal with cattle with respiratory disease.

The next video begins with an excellent explanation of BRD. It is included for information purposes only, and does not constitute or imply an endorsement, recommendation, or favoring by the BCRC or the CCA.

Clinical Signs

Historically, feedlot cattle exhibiting signs of depression separate themselves from the rest of the pen. This generally occurs within the first two weeks after arrival to the feedyard. Body temperature has been used to determine whether they should be treated. Body temperature is such an important diagnostic test that many feedlots will treat animals based upon an undifferentiated fever (UF). 

Classical clinical signs of bacterial BRD include:

      • fever of over 40°C (>104°F)Subscribe to the Beef Research blog
      • difficulty breathing occurred to varying degrees
      • nasal discharge
      • varying degrees of depression
      • diminished or no appetite (‘off-feed’)
      • rapid, shallow breathing 
      • coughing 

BRD may not always be “arrival associated” and frequently occurs after the stock attendants have reduced their level of surveillance of the newly arrived animals While diligent pen checkers will usually identify most sick animals, this is not always the case. It is believed that some infectious agents such as Mycoplasma do not produce the toxins that other bacteria do, and hence the animals do not appear depressed. Thereforeit is easier to overlook these animals. Often times, when selected, cattle will display a profound exercise intolerance (hard to get out their “home” pen), obvious breathing difficulty, very little evidence of appetence and show a poor or prolonged response to treatment. 

Risk factors

Ultimately, a mixture pathogens is usually responsible for BRD, but as previously stated a number of other factors influence the susceptibility to developing BRD. Any one risk factor alone may be insufficient to trigger cases of BRD, but together they form an additive effect that can predispose the animal to BRD.  

Environmental factors, particularly transport, have been associated with BRD for decades. Historically, cattle were often shipped by train, particularly to large markets in the United States. It was recognized at the time that shipping was a risk factor for BRD, and hence pneumonia in cattle was termed “Shipping Fever”.  Today, we still rely heavily on the use of thermometer to identify animals with a ‘fever’, which is essentially a tell-tale sign of BRD. A study involving calves arriving at 21 US commercial feedlots from 1997 to 2009 concluded that distance traveled was correlated to the incidence of BRD. This, however, has not been substantiated in western Canada. 

Weather has always been implicated in the occurrence of BRD, presumably because the greatest incidence of BRD occurs during the fall. However, this finding is confounded by the fact that it is also when the greatest number of calves is being assembled, mixed (commingled), and transported. A study involving 288,388 head of cattle, arriving at 9 US commercial feedlots during September to November in 2005 to 2007, found that maximum wind speed, mean wind chill temperature, and temperature change were associated with an increased incidence of BRD. 

A number of studies have found a higher incidence of BRD in auction market versus ranch-derived calves. Furthermore, the incidence of BRD increases with the level of commingling; calves assembled from multiple lots are more likely to have BRD than are pens composed of larger groups of calves. In addition, there is considerable anecdotal evidence that the quality of the calves purchased is highly associated with the incidence of BRD; with poorer quality calves having more BRD. 

A preponderance of studies found that lighter weight calves have a higher risk of developing BRD than do their heavier penmates. 

A large-scale U.S. study involving 21 million animals found that from the years 1997-1999 females were at a greater risk of developing BRD than were males, but no difference in gender was found for the years 1994-1996. 

Most studies looking into the effects of dehorning and castration only examined performance parameters (ADG, feed:gain); however, it is inferred that these stressful events, and others like calving or the rapid  introduction to high grain rations, may precipitate cases of BRD. 

The risk factors associated with an outbreak in a particular feedlot may or may not exist in outbreaks involving similar types of animals in similar settings.  

Prevention

Before calves are marketed

Preconditioning appears to have some benefit in preventing BRD, with weaning prior to the sale being the most important component of a preconditioning program. The concept of preconditioning calves to decrease stress levels was first introduced in 1967. While there is considerable variation in what constitutes a preconditioning program, the central components entail:

There appears to be agreement that weaning and/or vaccinating at least 3 weeks prior to shipping is beneficial.
  • vaccination for respiratory viruses and bacteria
  • weaning days to weeks in advance of sale
  • administration of clostridial vaccines
  • dehorn and castrate far enough in advance of sale for complete wound healing
  • training calves to bunk feeding

The concept of preconditioning has been largely accepted in Alberta; many feedlots prefer to “place” calves in winter (January, February) recognizing such groups of calves have very likely been weaned and “bunk broke” thus completing the most important management aspect.

After calves arrive at the feedlot

Vaccines for respiratory diseases are routinely administered upon arrival at the feedlot, which may also be a difficult time for a stressed calf to mount an effective immune response. A recent review of the scientific literature found no clear benefit from vaccinating calves upon arrival at the feedlot. Another review relating to Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni vaccines concluded that there was a potential benefit for vaccinating feedlot cattle against M. haemolytica and P. multocida but not H. somni. 

Nutrition may affect incidence of BRD. One review found that increased energy density (concentrates) will improve ADG without adversely affecting the incidence of BRD. Other studies found that the incidence of BRD tended to increase once concentrates exceeded 50% of the diet. Similarly, BRD morbidity increased once crude protein exceeded 14%. There is not enough evidence to conclude that injected doses of vitamins A, D, and E will reduce BRD. A wide range of studies have also examined supplementing with potassium, thiamine, B-vitamins, copper, zinc, vitamin E, selenium, and bypass protein, but none have significantly affected the incidence of BRD. 

Metaphylactic treatment strategies can help control BRD in high risk calves, but feeding oral antimicrobials, either by water or feed, may not be effective since stressed cattle may not be eating their feed. An analysis conducted in the early 1990s concluded that there was a lack of studies to justify the use of mass medicating with oral antimicrobials. Two subsequent studies found that inclusion of chlortetracycline and sulfamethazine in the ration reduced BRD treatments and morbidity. If treating on arrival it is important to use antibiotics labeled for control of BRDWith the introduction of new regulations governing the use of antibiotics, it is important that producers consult with their veterinarian regarding the use of antibiotics for the control and treatment of BRD. 

General animal husbandry can also help reduce the risk of disease. Providing clean dry bedding, avoiding overcrowding, using low stress handling techniques, proper ventilation of barns, and minimizing dust can help to reduce disease.  

Treatment

The literature contains a large body of knowledge regarding the beneficial effects of antimicrobial therapy in the treatment of BRD. The question is not, whether to treat with an antimicrobial, but rather, “which antimicrobial works best?” There is no simple answer to this latter question. 

Ancillary drugs, such as nonsteroidal anti-inflammatories (NSAIDS) and immunomodulators, have been used to treat BRD for decades. However, many of the studies have been used on experimental models and there is a lack of data from well-designed, large-scale, clinical trials. That said, a more recent study found that meloxicam (NSAID) administered prior to castration significantly reduced the number of animals to develop BRD. 

Even when working with the best recommendations, sometimes treatments fail. Common causes of treatment failure include; 

  • Pathology of the lesion too far advanced 
  • Wrong diagnosis 
  • Simultaneous disease process (e.g.: Overt IBR, Post calving metritis) 
  • Inadequate dosage (e.g. MIC for the organism is higher than “label dose”) 
  • Overuse or inappropriate use of Ancillary Pharmaceutics 

Doing necropsies on sick animals early on in an outbreak can help to diagnose and treat the problem more quickly and accurately. If done early enough in the outbreak a necropsy can help your veterinarian define what the disease is and will give you enough time to develop protocols to deal with the disease appropriately.  

Carcass Quality Considerations

Current Research

Research into BRD is happening on numerous fronts. Current research is looking at better understanding the respiratory microbiome and the differences in the microbiome between healthy and sick cattle. Current research is also looking into antimicrobial resistance, improving, vaccines as well as getting a better understanding of the disease complex.

References

1. Radostits, OM, Gy CC, Hinchcliff KW, Constable PD. In Veterinary Medicine, A textbook of the diseases of cattle, sheep, pigs, and goats. Saunders Elsevier, Toronto, 2007. Pp 923-934.

2. Larson RL, Step DL. Evidence-based effectiveness of vaccination against Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni in feedlot cattle for mitigating the incidence and effect of bovine respiratory disease complex. Vet Clin North Am Food Anim Pract. 2012 Mar;28(1):97-106.

3. Francoz D, Buczinski S, Apley M. Evidence related to the use of ancillary drugs in bovine respiratory disease (anti-inflammatory and others): are they justified or not? Vet Clin North Am Food Anim Pract. 2012 Mar;28(1):23-38.

4. Cernicchiaro N, White BJ, Renter DG, Babcock AH, Kelly L, Slattery R. Effects of weight loss during transit from sale barns to commercial feedlots on health and performance in feeder cattle cohorts arriving to feedlots from 2000 to 2008.J Anim Sci. 2012.

5. Cernicchiaro N, White BJ, Renter DG, Babcock AH, Kelly L, Slattery R. Associations between the distance traveled from sale barns to U.S. commercial feedlots and overall performance, risk of respiratory disease and cumulative mortality in feeder cattle during 1997 to 2009. J Anim Sci. 2012.

6. Cernicchiaro N, Renter DG, White BJ, Babcock AH, Fox JT. Associations between weather conditions during the first 45 days after feedlot arrival and daily respiratory disease risks in autumn-placed feeder cattle in the United States. J Anim Sci. 2012 Apr;90(4):1328-37.

7. Taylor JD, Fulton RW, Lehenbauer TW, Step DL, Confer AW. The epidemiology of bovine respiratory disease: what is the evidence for preventive measures? Can Vet J. 2010 Dec;51(12):1351-9.

8. Taylor JD, Fulton RW, Lehenbauer TW, Step DL, Confer AW. The epidemiology of bovine respiratory disease: What is the evidence for predisposing factors? Can Vet J. 2010 Oct;51(10):1095-102.

9. Wildman BK, Perrett T, Abutarbush SM, Guichon PT, Pittman TJ, Booker CW, Schunicht OC, Fenton RK, Jim GK. A comparison of 2 vaccination programs in feedlot calves at ultra-high risk of developing undifferentiated fever/bovine respiratory disease. Can Vet J. 2008 May;49(5):463-72.

Learn More

To learn more on this topic, see the fact sheets posted on the right side of this page. External resources related to this topic are listed below.

BRD Report: From the Fence Post
Merck Animal Health
http://brdreport.wordpress.com/

Bovine Respiratory Disease
Intervet RESFLOR GOLD
Video
This video provides an excellent explanation of BRD through demonstration of how animals become infected and a possible treatment option.
Disclaimer: The appearance of, or reference to, specific commercial products, processes, or services by trade name, trademark, manufacturer, or otherwise on this website is for information purposes only, and does not constitute or imply its endorsement, recommendation, or favoring by the Beef Cattle Research Council (BCRC) or the Canadian Cattlemen’s Association (CCA).
http://www.youtube.com/

Infectious Bovine Rhinotracheitis (IBR)
Alberta Agriculture and Rural Development (AARD) Alberta Feedlot Management Guide
Summary of developments in the occurrence of IBR in feedlots and discusses developments in research on more effective vaccines.
http://www1.agric.gov.ab.ca

Bovine Respiratory Syncytial Virus (BRSV)
AARD Alberta Feedlot Management Guide
Overview of the virus, as well as symptoms, treatment and prevention.
http://www1.agric.gov.ab.ca

Bovine Viral Diarrhea (BVD)
AARD Alberta Feedlot Management Guide
An overview of the virus, as well as symptoms, treatment and prevention.
http://www1.agric.gov.ab.ca

Bovine Viral Diarrhea (BVD) Update
AARD Alberta Feedlot Management Guide
A summary of developments that recognize antigenic differences between type 1 and type 2 BVD viruses.
http://www1.agric.gov.ab.ca

Cross-Sector Practices: From a Veterinarian's Perspective
Saskatchewan Beef Industry Conference

https://www.youtube.com/watch?v=1pRM5U1mCWc

 

Feedback

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Acknowledgements

Thanks to:

  • Dr. Murray Jelinski, Professor and Alberta Chair in Beef Cattle Health and Production Medicine at the Western College of Veterinary Medicine, University of Saskatchewan
  • Dr. Eugene Janzen, Professor in the Department of Production Animal Health and Assistant Dean Clinical Practice at the University of Calgary

for contributing their time and expertise to writing this page.

 


This topic was last revised on November 29, 2018 at 3:11 AM.

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