How Does Your BRD Antibiotic Measure Up?

Your bovine respiratory disease (BRD) antibiotic has an important job to do. How do you know that it is working?

The metrics below — some of which your operation may already track — provide a great starting point for measuring the success of your BRD treatment and control antibiotics.

Use these metrics independently or in combination to help identify strengths and opportunities within your BRD program as well as guide a conversation with your veterinarian about any necessary improvements.

Measuring Success of an Antibiotic for Treatment of BRD

1. Lower Re-treat and Repull Rates

You are likely assessing these rates together, as many operations do, but some operations have found it helpful to differentiate between the two when measuring treatment success.

    • Re-treat: Is usually seen as a failure of the antibiotic for the first treatment and there is a need for further intervention.
    • Repull: Is usually seen as a relapse or reccurence of disease, rather, a new instance of BRD and not necessarily a failure of the first antibiotic.

Whether evaluating together or separately, consider that there are many factors, including management practices and changes in the number of cattle you’re receiving, that can increase your re-treat and repull rates.

2. High Clinical Response Rate

Clinical symptoms can be very subjective, but you can objectify them by using DART criteria to guide your evaluations:

    • Depression
    • Appetite
    • Respiratory rate and character
    • Temperature

If you have a scale in your chutes, weight can also prove a valuable metric, with weight gain or maintenance supporting a positive clinical response.

To improve clinical response rates, consider a BRD product with a longer post-treatment interval (PTI), or time active in the animal’s system. DRAXXIN® (tulathromycin) Injectable Solution, for example, has a demonstrated PTI of up to 14 days.1-4

3. Low Case Fatality Rate

Case fatality rate is the percentage of cattle pulled that actually die of BRD. A rate of 10%-20% is generally acceptable, but, as mentioned above, pull rates can be influenced by many outside factors.

Exercise caution during interpretation as a low case fatality rate does not always indicate a successful treatment program.

    • 1 death/2 pulls = 50% case fatality rate
    • 10 deaths/100 pulls = 10% case fatality rate

In this example, the herd with a 50% case fatality rate would still experience fewer death losses and treatment expenses.

Measuring Success of an Antibiotic for Control of BRD

1. Lower BRD Morbidity (Pull rates)

Herds that receive an antibiotic on arrival should have lower BRD morbidity, or pull rates, than untreated herds. In theory, less-effective antibiotics would also be associated with higher pull rates.

However, keep in mind that pull rates may be increased by other factors. Using antibiotics that are active for shorter lengths of time in the animal’s system (also called post-metaphylaxis intervals, or PMIs) or if employees aren’t pulling the right cattle at the right time, may influence pull rates.

This article shares a few more reasons why your pull rates could be higher.

2. Lower BRD Mortality

Mortality is considered a critical measurement of BRD treatment success as it is usually seen as the greatest expense of BRD. Death losses include yardage, feed and medicine costs on top of the animal’s purchase price. Those costs can be so steep that cattle owners, particularly custom cattle feedlot owners, often prioritize mortality above overall performance and cost of gain.

Though factors outside of antibiotic efficacy can also influence mortality, the metric itself is fairly objective and easy to track. You can work to reduce your mortality rate with an antibiotic that’s demonstrated to reduce death loss by up to 50%.

3. When Pulls Occur

When morbidities and mortalities occur can be just as important as their frequency. BRD morbidity and mortality curves can reveal trends in timing and help distinguish between antibiotic failures and previously acquired disease.

Cattle that fall ill or die within the antibiotic’s PMI are often those that acquired BRD prior to arrival and, in the case of mortalities, already may have extensive, irreversible damage. Performing necropsies on animal’s that die within the PMI period is critical to assess if there is pneumonia and the extent, severity and age of the disease process. Later occurrences of morbidity and mortality can be an indication of antibiotic failure.

4. First Treatment Response Rate

It is unrealistic to expect metaphylaxis to completely prevent BRD. However, effective metaphylaxis should improve the outcome of any first treatments for BRD outbreaks. The antibiotic used for control may have as much or more impact on first-pull treatment success than the actual antibiotic used for first-pull treatment.

High instances of re-treats may indicate an antibiotic failure during metaphylaxis or treatment.

5. Lower Chronic Rate

The number of cattle that have been treated for BRD three times or more, known as “chronics,” can also indicate metaphylaxis efficacy. If chronic rates are high, you may want to talk to your veterinarian about different antibiotic and husbandry options or put sick cattle in “restart programs”— a high-quality forage program in which animals are typically turned out on wheat or grass pasture and receive high-value nutrition, stress management, shade and plentiful water supply — to help improve BRD outcomes.

6. Performance and Carcass Quality Impacts

While antibiotics do not impact carcass quality and performance directly, we know that animals that are never pulled for BRD or respond rapidly to a first treatment are on feed for less time, gain weight more effectively and have desired carcass traits. Research has shown that animals pulled once, twice or even three times for BRD have significant grade and carcass impacts.5

Bottom line: Controlling BRD more successfully all the way to harvest can mean metaphylactic success and the derived benefits of improved performance and better carcass traits.

If your BRD treatment and control metrics aren’t measuring up to your expectations, don’t count your antibiotic out right away. Talk to your veterinarian to troubleshoot your BRD program so you can keep working toward  healthier, more profitable cattle.

While you’re evaluating your BRD treatment and control protocols, make sure to estimate how much those programs are costing your operation with this handy calculator.

IMPORTANT SAFETY INFORMATION: DRAXXIN has a pre-slaughter withdrawal time of 18 days in cattle. Do not use in female dairy cattle 20 months of age or older. Do not use in animals known to be hypersensitive to the product. See full Prescribing Information.

1 Food and Drug Administration. Freedom of Information Summary: Original New Animal Drug Application, NADA 141-244, DRAXXIN Injectable Solution (tulathromycin). https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/789. Published May 24, 2005. Accessed August 7, 2019.
2 Data on file, Study Report No. 1131R-60-05-485, Zoetis Inc.
3 Data on file, Study Report No. 1133R-60-09-749, Zoetis Inc.
4 Data on file, Study Report No. 1133R-60-05-489, Zoetis Inc.
5 Cernicchiaro N, White BJ, Renter DG, Babcock AH. Evaluation of economic and performance outcomes associated with the number of treatments after an initial diagnosis of bovine respiratory disease in commercial feeder cattle. Am J Vet Res. 2013;74(2):300-309.

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