How does the immune system respond to respiratory disease in cattle?

"Cattle are dependent on their immune system as a primary defense against invading organisms, viral or bacterial. The immune system generally functions quite well but is subject to compromise during stressful situations." David McClary, DVM, MS and Elanco technical consultant, describes how the immune system works and the factors that can sometimes compromise an animal's ability to fight infection.

Despite advancements in technologies to combat BRD in recent years, stocker operations handling commingled cattle still face significant respiratory losses associated with deads and pulls, and many times, don’t have a good handle on exactly what the disease costs them. Blue says losses are extremely variable, but can easily be in excess of $100 per head.¹

“BRD is a continual fight,” he says. “And the economic losses are expressed in a variety of ways, including treatment, morbidity and mortality costs, as well as losses associated with decreased performance. A frequently missed point is the added cost in labor and time.”

The potential for BRD losses and a limited ability to detect the disease in its early stages are major reasons to consider metaphylaxis treatment. Metaphylaxis allows the producer to impact the disease process in the early, developmental stages. Blue recommends Micotil^® (tilmicosin injection) metaphylaxis to address both BRD risk and animal weight variation in commingled calves. 

Because Micotil is the only metaphylaxis treatment approved for a flexible dose range (1.5 mL/cwt to 3.0 mL/cwt), veterinarians are able to address a common risk factor in commingled calves. When calves are dosed based on the average weight within a truckload, there are times when a significant percentage of cattle can be under dosed.  Because these calves were under dosed, they can be at a higher risk for disease development.

As an example, Blue cites a study in which the weight variation in a group of 1,200 cattle was examined.  In this example, dosing based on the average weight at 1.5 mL/cwt would have delivered an adequate dose to only 54 percent of the cattle.² Increasing the dose of Micotil an additional 0.5 mL/cwt would have delivered an adequate dose to 100 percent of the group.  “There can be a lot of weight variation within a truckload of cattle and with Flex Dose, you can ensure heavier and/or higher risk cattle get the appropriate dose,” says Blue.

Using Micotil metaphylaxis provides proven benefits as shown by 34 studies of more than 18,000 head of cattle, which included a variety of cattle types and risk factors across all areas of the country.³ “When consulting with your stocker clients about the benefits of metaphylaxis compared to pull-and-treat programs, the most differentiating factors are the reduction in pulls, death loss and treatment cost,” says Blue. “For high-risk cattle, metaphylaxis will consistently be a more economical choice because you’re controlling the disease upfront, while it’s still in its developmental stage.”

Safe handling and use of injectable products – role of the veterinarian

The safe handling and use of all injectable products begins with veterinarians who have a critical role in the education and training of cattle-processing crews. Blue says that education focused on using adequate facilities to properly restrain animals and handling loaded syringes with care can help prevent accidental exposures.

“A cornerstone of our customer service to veterinarians and their clients is that we offer face-to-face training to ensure our customers are comfortable with the administration of all injectable products. We offer a variety of safe handling and use training tools and resources, in both English and Spanish,” says Blue.

Elanco also offers a safety syringe designed with a double-action administration process. The needle guard protects the user from exposure until the time of injection. A double-action trigger and the ability to give the injection with one hand decreases the chance of accidental exposure.

“As a veterinarian and as a technical consultant for Elanco, I’m very dedicated to the safe handling and use of all pharmaceutical products,” says Blue. “We have a responsibility to our producers to help make sure pharmaceutical products are used safely and responsibly.”

If you or your clients would like to set up an on-site safe handling and use training demonstration or if you would like to order training materials, please call 1-800-428-4441.

Important Safety Information

See label for complete use information, including boxed human warnings and non-target species safety information. Micotil is to be used by, or on the order of, a licensed veterinarian. For cattle or sheep, inject subcutaneously. Intravenous use in cattle or sheep will be fatal. Do not use in female dairy cattle 20 months of age or older. Use in lactating dairy cattle or sheep may cause milk residues. The following adverse reactions have been reported: in cattle: injection site swelling and inflammation, lameness, collapse, anaphylaxis/anaphylactoid reactions, decreased food and water consumption, and death; in sheep: dyspnea and death. Always use proper drug handling procedures to avoid accidental self-injection. Do not use in automatically powered syringes. Consult your veterinarian on the safe handling and use of all injectable products prior to administration. Micotil has a pre-slaughter withdrawal time of 42 days.

¹Brooks, K, KC Raper, CE Ward, BP Holland, and C Krehbiel. 2009. Economic Effects of bovine respiratory disease on feedlot cattle during backgrounding and finishing phases. Southern Economics Association Annual Meeting.

²Elanco Study No. T5CB39905.

³McClary, D, B Carter, M Corbin, C Guthrie, S Laudert, J Mechor & G Vogel. 2010. The Use of Micotil^® (tilmicosin injection) Metaphylaxis for the Control of Bovine Respiratory Disease (BRD): A 34-study Summary. Elanco Data on File.

Micotil^® is a trademark for Elanco’s brand of tilmicosin injection.

© 2011 Elanco Animal Health.

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