Ask A Farmer: Use of Antibiotics in Cattle Feedlots

Antibiotic Use in Livestock and Resistance
Image via: The Samuel Roberts Noble Foundation

Last week, I brought forward some Food For Thought on the issue of antibiotic use in livestock. The concerns surrounding an increase in antibiotic resistance seem to raise a lot of emotion and controversy around our food supply, just as the use of other feed additives, chemicals, herbicides, and countless other technologies and applications of science. I have addressed some of these subjects as they relate to beef cattle production in my Ask A Farmer series.

When I asked others involved in livestock production to share their experience with the use of antibiotics, I had a few replies. Andrew Goodrich was one of the first to respond with a lengthy answer, so I will share some of his responses. We haven’t agreed during more than a few conversations online, but I have to respect his experience in the field. Andrew has worked on several cattle feedlots in the Northwest and Canada and has a first-hand point of view on how antibiotics are used in cattle production.

I have spent much of my life doing business with and working in the cattle feedlots, as explained in many previous posts, but I think it will be good to share another perspective from someone else involved in the business.

Are feedlot cattle given antibiotics through their feed?

Ionophores are probably the most commonly used. You will find them in yards that feed 100,000 head and yards that feed 50 head. They are growth promotants, but the advantages to animal health are often overlooked. They prevent bloat and acidosis. Both of these events happen incredibly fast and are often fatal to cattle. The worst wreck I’ve ever experienced happened when 5,000 yearlings were put on hot ration without monensin. In the end, we lost 50 animals to grain overload. Ionophores also prevent coccidiosis, which can be detrimental to an animals and performance.

Ionophores are classified as an antibiotic, but they are not therapeutic antibiotics. Antibiotic resistance is an increasing concern in public discourse. However, the increase in antibiotic-resistant bacteria as a result of ionophore use is not well supported for a number of reasons: ionophores have never been (nor are likely to be) used as antimicrobials for humans and ionophores have a very different mode of action from therapeutic antibiotics. Read more from University of Florida.

Medicated feed (Chlorotetracycline; CTC) is another tool we use to treat cattle. We can use it to extend antibiotic coverage in fresh calves, treat illness associated with ration transitions, and to aid in the treatment of a large number of sick animals at any time during feeding period.

Do all cattle in the feedlot receive CTC medicated feeds?

In some yards, all cattle receive CTC. It really depends on the type of cattle, time of year, and how an outfit decides to use it. When I worked in Washington, all cattle received it once as they went through the ration transitions. If at any time during the feeding period we noticed excessive coughing and nasal discharge, we would use CTC again, as well as exercise to turn them around.

Do feedlot cattle receive any injections of antibiotics as a preventative measure?

antibiotics fed to cattle in a feedlot
CTC medicated feed additive in the bunk for cattle

Antibiotics are also used for the prevention of Bovine Respiratory Disease (BRD). Cattle are prey animals and incredibly stoic. They survive by hiding illness from anything the perceive as a threat. Combine this with a lack of pen riders, and the need for metaphylaxis on arrival becomes very necessary. In our yard, all high risk fall and winter placed calves receive tulathromycin on arrival to help get them through the most stressful time of the feeding period.

What do you mean by “high risk” cattle?

We define high risk calves as freshly weaned animals sourced through a sale barn. They are stressed from weaning and are exposed to bacteria and viruses from many different operations. These are prime conditions to create a sick animal.

When do feedlot cattle receive antibiotic treatments for sickness?

The last way we use antibiotics is for individual animal treatment. This could be for anything from BRD to footrot or acidosis. In our yard, sick cattle are pulled by cowboys and brought to the hospital, where we use a thermometer, stethoscope, and visual assessment to diagnose and determine the severity of an animals illness.

How do you determine which antibiotic treatment feedlot cattle receive?

We also use diagnostic trees to pinpoint lameness in the animals. After the appropriate antibiotic is administered, the animals either return to their home pen or stay in a recovery pen, depending on their condition. We have about 10 different antibiotics in our selection, although about 90% of critters respond to one treatment.

What is the maximum number of times an animal will get treated with antibiotics? When do you decide to stop treating the animal?

cattle feedlot antibiotics
Fresh cattle in a feedlot often receive a lot of hay/roughage. Antibiotics isn’t the only method used to keep animals healthy. Mostly it is wise management.

Typically, an animal will receive no more than 3 or 4 treatments (only 1% of animals ever get to this point). However, if we think the animal will respond and improve, we will treat as many times as necessary. When we hear consolidation and referred sounds in the lungs, an animal is determined to be chronic and treatment is either ceased or altered, depending on treatment history, condition, and amount of consolidation in the lung.

Cattle feedlots are the last step in beef production before slaughter. How do you make sure antibiotics do not end up in our beef supply?

Regardless of how an animal receives antibiotics, they are entered into the computerized record keeping system. This helps administer the proper dosage, track an animals progress, and observe proper withdrawal times. Every antibiotic has its withdrawal right on the bottle. We enter it in the computer and every time an animal receives treatment, its “clear date” is displayed on the treatment, movement, and shipping programs. Before a pen is harvested, we check withdrawals and remove any animals if necessary.

One last question. I often get the response of “Well, if you didn’t have these animals in such a crowded place, they wouldn’t have to receive antibiotics.” How would you respond to someone saying that?

I love cattle, but they are one of the most poorly designed creatures on the face of the Earth.  A vet once described them to me as a car with 4 engines and one radiator. There will be animals that get sick and require antibiotics regardless of where they are. Also, land is valuable and scarce. Around here, 160 acres goes for 1.4 million dollars. We can produce much more protein sowing that to corn or barley and feeding that to cattle than we could turning cattle out on that land.

cattle feedlot antibiotics
The ultimate destination for cattle in feedlots is the beef slaughter plant. We take that responsibility of producing safe beef very seriously.

I hope that Andrew’s insight has given you a glimpse of the complexity that goes into taking care of cattle in a feedlot. It is important to note that many conditions seen inside a feedlot (CAFO) are also seen when cattle are raised on pasture. As a person who has been there and worked alongside feedlot pen riders and veterinary crews, it is not an easy task and is hard work in all the weather elements mother nature brings. Taking care of their cattle is also first priority among most of these men and women and I cannot even begin to understand some of the misperceptions and hatred that exist toward the folks who dedicate their lives to raising cattle for our beef supply. The feedlots are the last step in raising cattle for beef prior to slaughter and a sector of the business which is underrepresented in food dialogues occurring today. Thank you Andrew for sharing your experience with us.

Do you have questions about antibiotics, feed additives, or any other aspects of livestock production? Feel free to leave a comment below or send me a private message through the Contact page.

Are you a livestock producer? When was the last time you took the opportunity to share your experiences on using antibiotics or other tools in livestock production? Please, send me a note or an entire guest post. I am more than willing to share your experience with my readers.


  1. This is a great article!

    I do think though, that the use of the word farmer is used incorrectly (in countless situations) to describe western ranches. Many western US ranches, do NOT farm, and they do not receive the subsidies farmers do. If they raise a crop, it’s usually something they keep at home to feed their replacements; they’re not raising a crop to feed the world. Ranchers are NOT guaranteed x number of calves come spring, and they’re not guaranteed x number of calves to sell come fall. There’s no safety net there for ranchers, and I for one, would like to see the term farmer NOT used when it comes to beef production in the western US.

    I suppose this is my own personal pet peeve. 🙂 Thanks for all you do, Ryan!

    1. Great point, and I kinda agree Jenn. Unfortunately, More folks are searching for “Ask a Farmer” than “Ask a Rancher” so this series reaches more folks searching for answers with the term Farmer. No disrespect intended.

  2. ” It is important to note that many conditions seen inside a feedlot (CAFO) are also seen when cattle are raised on pasture.”
    Please explain this statement…

    1. I often get challenged that cattle would not get sick or need antibiotics if kept on pasture instead of feedlot. This is not true. Illnesses like coccidiosis, bloat, respiratory, foot rot still exist in pastured herds. I think that is an important point to note in the conversation.

      1. Even in our closed cow herds we can have devastating illness run through them like a wild fire. It is unclear way this occasionally happens.
        The most probable cause is coccidiosis carried by birds.

  3. Just a quick question Ryan. Do cattle that have issue with sickness often get culled from herds? Would this not require culled cows being sent to feedlots to be provided with antibiotics more often than those cows being kept for herd expansion?

    1. Most cows (mature cattle) when culled for various reasons are sent to a different slaughter plant than feedlot finished young cattle. Some producers may retain their cull cattle for a short period of time at home place to put some weight (<100Lbs) on before selling for cull cow slaughter.

  4. This blog addressed a lot of the questions about how antibiotics are used on this specific feedlot (which was very informative — thank you!), but I have more! Do you think non-therapeutic antimicrobials are necessary? Is their use worth the risk of horizontal gene transfer and movement of resistance? Or does the animal ag industry need to change, as suggested by The Lancet’s recent editorial re. antibiotic resistance? If so, what would it take to phase them out?

    1. This perspective from Andrew represents management similar to what I have seen in the many feedlots where I have worked and visited.

      Usually when we use metaphylactic treatment (treatment described and defined in hyperlink above) it is a management decision to prevent more medicine being used in calves that are at a higher risk of becoming sick. When I was making this decision in the feedlot, I had a specific threshold for number of animals treated for illness before prescribing metaphylactic treatment.

    2. Debra,
      Non therapeutic antibiotics (ionophores) are very necessary when we feed high energy rations. In terms of antibiotic resistance, it’s my understanding that ionophores never have and never will be used be used in human medicine, making it a bit of a moot point.
      Ryan hit the nail on the head pretty square about metaphylaxis. And does the industry need to change? Of course we do, but I don’t think doing away with antibiotics as a treatment for sub acute illness is the way to go. We only have to look as far as Denmark to see it’s a bad idea.

  5. It’s quite a great idea including antibiotics in animal feed only if the dose is strictly adhered to. More so, farmers should be enlightened to know the dangers associated with dosage abuse especially in Africa.

  6. My sister works on a feedlot, and one of the topics that she usually talks about is how antibiotics were being used on the feedlot. She will attest to the fact that the utmost care is taken to make sure that correct antibiotics are used in the correct dosages to take care of the animals. Also, a lot of care is taken to make sure that the cattle have plenty of time to go through the withdrawal period so that the quality of the meat is not affected.

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