Most clients tend to overemphasize the role of antibiotics in therapy.
Cattle producers don’t want to see animals get sick, and when they do fall ill, producers want to see them get better ASAP. That means there is a lot of emphasis on determining which antibiotic is the best option for treatment. However, as veterinarians we understand there is quite a bit of nuance as to why animals recover and when they recover. Our clients often don't understand this nuance.
This creates a lot of pressure on discovering that “silver bullet” antibiotic, so much that producers can quickly condemn a drug that doesn’t immediately meet their treatment expectations. Unchecked, this can lead to unnecessary re-treatments that may not meet judicious use guidelines.
To combat this misconception, we need to help our clients understand what they should expect from using an antibiotic in treatment of cattle disease. With this knowledge, they will know what realistic antibiotic performance is, which should encourage them to continue to use them appropriately.
Have the conversation
The ideal time to talk about all this to producers is not when you’re in a hurry between calls. Rather, pick a time and place that allows you to fully explain the situation and concepts. Producer meetings are superb location. I think it’s best to break it down into three parts.
- Give the drug time to work.
- No, we can’t make it work faster.
- Not every treatment is efficacious.
1) Give the drug time to work. Most producers have a misconception of what antibiotics actually accomplish. They feel the antibiotic is the only aspect in curing the disease and understate the necessity of the animal’s immune system to work with the drug. In my conversations, using military metaphors have had the best success in illustrating the effects of antibiotics.
I start by explaining when antibiotic molecules happen to encounter the bacteria, they interact with the bacteria to stop it from completing normal cell functions—decreasing the amount of active, replicating bacteria the animal’s immune system needs to destroy. Comparing an antibiotic to a bombing campaign, with the animal’s immune system being the foot soldiers that clean up the disease, helps drive this point home.
A World War II style bombing campaign also explains the aspect of giving the drug time to work. Unlike guided missiles, an antibiotic does not have a homing device to send it right to the bacteria—both the bombs and antibiotic are sent out on their own. Therefore, it requires time for enough antibiotic molecules to successfully interact with the bacteria to decrease the infection.
2) Is there a way to speed up the antibiotic? A common question I get is whether changing the route of administration will expedite the process. Obviously, this needs to be discouraged for Beef Quality Assurance reasons as well as FDA instructions. To address the question of giving the antibiotic in a muscle closer to the site of the infection, point out the antibiotic still needs to be absorbed from that area and put into circulation.
People will also ask about intravenous administration. This is a great opportunity to speak about timely treatment. While acknowledging it does speed the process up by a few hours, point out that if an animal is so close to death that hours count, it will require more care than merely an antibiotic to change the course of its disease.
3) Not every treatment makes a difference. This is the part of the conversation that is the most difficult, but also the most necessary.
It runs counter to the common thought that the antibiotic we administer is the only reason an animal gets better. Being able to illustrate the number need to treat (NNT) principle in a clear manner is a challenge, but doable.
Using the FDA data on pneumonia in feeder cattle is an easy way to start. There our NNT is two. The passage that follows is how a person may have success in wording a discussion about the NNT.
In the FDA studies, the researchers use two groups of calves that have contracted pneumonia. For easy math, we’ll say each group had 100 calves in it. In the first group, instead of using an antibiotic the researchers injected the animal with sterile saline. On average in these studies, 25 of the calves got better on their own and 75 continued to have pneumonia. In the second group, they used an antibiotic. Here, 75 of them recovered and 25 of them continued to have pneumonia. This means the antibiotic helped 50 out of 100 calves recover. And that is considered good enough by the FDA to sell a product labeled for this problem.
Now, using this information let's consider what we see in the field. If we treat 100 calves for pneumonia, and 75 recover, we like to tell ourselves we saved 75 calves. But actually, since 25 of them were going to get better without treatment, it means we only helped 50 cattle. For those other 25 that got better, we wasted the antibiotic.
Does that mean we should stop treating calves? No, because our treatment made a difference in the outcome of the disease in one-half of the sick calves. But equally as important, it didn’t make a difference in one-half of the treated calves. That means for every two calves we treat for pneumonia, we are only helping one calf.
The presentation of this information typically is followed by a question of how we can determine which animals will benefit from antibiotic therapy and which animals won’t. This is where judicious use and preventative medicine can be slipped back into the discussion. It is also an opportunity for giving out protocols, which can be pre-printed on handouts for the producers.
Our role in education
We are all aware that scrutiny toward antibiotic use in cattle will increase for the foreseeable future. As the primary contact for producers’ antibiotics questions, we are uniquely positioned to address false assumptions about antibiotic capabilities. Having an honest discussion not only promotes judicious use, it puts the veterinarians who can communicate these messages as a go-to for producers in this increasingly cloudy environment. And for our profession, that is exactly the position I would like to see us in.