Antibiotic Stewardship in Calves – Part 3

Haley Zynda, Extension Educator, Agriculture and Natural Resources, Wayne County, Ohio State University Extension

We’re back with the final installment of the Antibiotic Stewardship in Calves program from Veal Quality Assurance. The final module is treatment protocols, a natural wrap-up to the  program after learning about both the role of antibiotics and clinical evaluations. The goal of Part 3 is to improve treatment accuracy according to veterinarian protocols, and by the end of it, we should be able to select strategies for individual calves (a one-size-fits-all approach is too broad when it comes to veterinary medicine).

So why are veterinary protocols important? Well, given the title of the course, one of the reasons is to reduce unnecessary antibiotic use. Additionally, avoiding illegal use of medicine, improving treatment success, improving animal welfare (a biggie in today’s consumer perspectives), and to decrease the risk of meat residues. Each protocol your vet gives you will have a set list of components: disease signs, medication and dosing, route of administration, use and frequency of treatment, length of treatment, meat withdrawal (if applicable), and follow-up. We’ll walk through each of these components with an example. With the temperature fluctuation of late, pneumonia is likely a “popular” illness right now, so we’ll use a respiratory disease example.

Think back to the clinical evaluation section and respiratory disease. Healthy calves should not have eye or nasal discharge, droopy ears, a cough, or abnormal breathing, scoring a 0 on all accounts. If a calf presents with any severity of the former list, they automatically receive a score of at least 2 for each sign. This is where decisions come into play; if the scores add to 2, don’t treat quite yet, just check on them the next day. If the scores add up to 4, take the calf’s temperature. A normal temperature indicates monitoring the calf further, but a temperature above 102.5˚F calls for treatment. Scores adding to 5 or more require immediate treatment, no temperature necessary. Decision trees can help guide when a certain type of treatment is necessary, but always consult with your veterinarian on specific antibiotic use!

Speaking of medications, there are several names that will appear on labels, depending on the brand you purchase. For example, Polyflex® is a brand name drug, but the generic name is ampicillin. Likewise, for Liquamycin® LA-200 (oxytetracycline) or Baytril® 100 (enrofloxacin). Dosing will also be listed on the bottle (1 cc = 1 mL), as will the route of administration. Adhering to the proper route of administration is extremely important, just look up the results when Banamine® is administered intramuscularly in horses. Medications can be given orally (per os), intravenously, subcutaneously (sub-q), or intramuscularly (IM); the neck is a popular spot for sub-q or IM injections because there are fewer economic losses down the line from site reactions in the muscle.

Frequency and length of treatment go hand-in-hand; frequency being how often you can administer medication, with length being the number of days the medication is given. Some drugs may have single-dose, single-day treatment options or multiple-day treatment options listed on the bottle, but check with your vet to ensure the correct one is given. Ensuring the correct drug is used for the disease at hand is also an essential part of the puzzle; using antibiotics for off-label use can ONLY be recommended by your veterinarian. So let’s put it all together.

We have a 100 lb calf with respiratory signs. Her eyes aren’t crusty, but she has labored breathing and some nasal discharge. These signs add up to a 6, so according to our decision tree, we can treat without taking her temperature (but can always do so for more information). After talking with our vet, it sounds like it may be pneumonia and is listed as a use for Polyflex® (ampicillin). This drug is given at a rate of 1 mL per 50 lb of body weight either IM or sub-q. We can treat the calf with 2 mL of ampicillin once per day for 3 to 7 days. Our little heifer calf will stay on the farm to become a replacement, so no withdrawal time is expected. However, on a veal operation, we would need to wait 8 days before sending the animal to slaughter.

The last part of the equation is recordkeeping. Creating and maintaining thorough records allows producers to monitor progress, or lack thereof, of individual animals and reduce the risk of drug residues in meat. Records are the only way to prove a treatment occurred.

In summary of the three-part series, antibiotics are a necessary drug to treat bacterial infections but can lead to negative human and animal health impacts if not used judiciously. Recognizing the clinical signs of disease and having a good working relationship with your herd vet allows for accurate and consistent use of antibiotic treatments. Many thanks to Drs. Pempek and Habing from Ohio State University for putting together this comprehensive and essential training.