Antibiotic Stewardship in Calves – Part 1

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

You’ve likely heard of Beef Quality Assurance, but what about Veal Quality Assurance? Essentially, it is the same type of certification for the well-being and proper handling of veal calves. However, a new addition to the certification training is antibiotic stewardship – a concept translatable to almost every livestock operation out there. The goal of the program is for farm personnel to correctly identify calves for treatment using a treatment protocol written by the herd veterinarian, thus improving responsible use of antibiotics. Drs. Jessica Pempek and Greg Habing put together a three-part training, of which I’ll summarize each with their own article.

Part 1 of the Antibiotic Stewardship in Calves is titled “Antibiotic Use and Resistance.” Before we jump into details, do you know the specifics on different types of medication? What do antibiotics treat? If you answered viral, fungal, protozoal, or parasitic infections, unfortunately you’d be incorrect. An antibiotic is a medicine that inhibits the growth of or kills bacteria. Antibiotics are not to be used to treat any other type of infection.

How about vaccines? They’re a hot topic right now in human medicine, but their purpose is the same in livestock. They introduce a viral or bacterial pathogen in an inert form to prime the immune system to attack it, should the animal be exposed to the pathogen in real time later. Vaccines can be a modified-live form, killed form, or conjugate form, and cause the body to recognize and make antibodies against that specific disease-causing organism. Vaccines prevent disease, not cure it.

Lastly, what about NSAIDs, or non-steroidal anti-inflammatory drugs? These drugs are the parallels to our ibuprofen or acetaminophen. These drugs do not prevent disease or cure infections, but instead reduce fever or inflammation that may be associated with an infection. Examples include flunixin meglumine, phenylbutazone, or meloxicam.

Now, back to antibiotics. It’s important to remember, not all bacteria are bad. There are very good bacteria that live in the digestive tract of calves and mature cows (the rumen wouldn’t function without them!). The bad bacteria are referred to as pathogens, and these bacteria cause the naval infections, pinkeye, and some pneumonia and diarrhea cases we see in calves. When using antibiotics, the medication does not pick and choose which bacteria it kills, other than using its mode of action (way of prohibiting bacterial growth). That means good bacteria along with pathogens are impacted when administering an antibiotic. Bacteria in the digestive tract unfortunately may take a hit, too. This will likely cause a disruption to the gut microbiome and digestion efficiency, and those good microbes will need to be repopulated again.

Overusing antibiotics or misusing them can lead to antibiotic resistance, or resistance by the bacteria to the antibiotic. Widespread resistance can eventually lead to bacterial populations unable to be controlled by medication for both livestock and humans. We, as humans, can be infected by the same or similar pathogens as livestock because we share segments of the gene pool (we’re all in the mammalian family). Therefore, antibiotic resistance not only affects livestock producers, but the lay people as well.

Overusing or misusing antibiotics causes resistance by selecting for the bacteria that are not killed or inhibited by the medicine. For example, let’s say there is a 5-day old calf presenting with diarrhea. For this age of calf, the causative pathogens may be E. coli, clostridia, cryptosporidium, rotavirus, or coronavirus. While waiting for the fecal culture results, you treat with an antibiotic. Fast forward after you’ve already given several doses of antibiotic – the culture is negative for bacteria and you’re dealing with a viral infection. Unfortunately, the antibiotics have already gotten to work. They’ve negatively impacted the good bacteria in the gut, and if there are any pathogenic bacteria in the system, have killed off the susceptible ones but left the resistant bacteria alone. The “lone rangers” will now have full access to replicate and pass on their resistant genes, potentially causing an issue down the line, especially if the same protocol is followed every time there is a sick calf.

Reducing the risk for antibiotic resistance starts with judicial antibiotic use. This means using the proper medication for the issue at hand. Having a veterinary-client-patient working relationship is essential to knowing when and when not to use an antibiotic. Discuss a treatment protocol with your vet. Using antibiotic alternatives may also reduce the chance of resistance. Minor infections may be handled simply using palliative care (giving an NSAID if the animal is in considerable pain, keeping a wound clean, providing fresh and dry bedding, etc.). Lastly, preventing disease before it occurs eliminates the need to use antibiotics entirely. Farm cleanliness, sick animal quarantine, and worker hygiene can all contribute to reduced disease transfer.

Reducing antibiotic resistance can start with anyone. Talk to your vet about antibiotic use on your farm and stay tuned for Part 2!