NCBA: Zoetis study shows long-duration re-implant boosts performance in long-fed cattle

19 February 2025

7 minute read

By: Lee Williamson

North America

Dr. Bryan Bernhard, a nutritionist with Zoetis based in the Lubbock, Texas area was recently interviewed by The Cattle Site’s Sarah Mikesell at the National Cattlemen’s Beef Association (NCBA) CattleCon Conference 2025 in San Antonio, Texas. 

How has the trend for cattle being on feed longer impacted the growth implanting strategies for feed yards? 

We continue to see feed yards having cattle on feed longer days, making those cattle heavier. It's just what the market dynamics have been asking them to do. When you have the beef on dairy crosses, those cattle come in the feed yards a little bit lighter and they're on feed even longer. We have traditional or conventional implants that last about 100 to 120 days. Those are commonly used in cattle that are on feed for less than 200 days. You can use a Synovex Choice and then follow it up with Synovex Plus. That would be a common re-implant program for shorter day cattle. As you get cattle on feed for longer days, there's been a lot of questions from a research perspective about whether we are comfortable stretching those implants longer or do we need to start working in a long-duration product like Synovex ONE feedlot into our re-implant programs to help cover cattle that are 230 or 240 or 280 days on feed. 

Recently Zoetis completed a study looking at two re-implanting strategies. Can you briefly explain how that study was set up? 

It was set up to answer that question for when cattle are on feed for more than 200 days. What's the right approach? Do we stretch those traditional implants? One treatment was a Synovex Choice followed by a Synovex Plus, so we stretched both of those. In another treatment they did a delay implant up front so no treatments for the first 30 days and then a Choice and a Plus to concentrate that hormone a little later in the feeding period to ensure we didn't run out. The third treatment plan was a Choice on arrival. Then we gave a Synovex ONE feedlot on day 80. Synovex ONE feedlot would last up to 200 days by itself. With the Choice, lasting up to 200 days, we got up to 280 days of coverage in this example. 

The long-duration products are coated so they release more evenly and consistently over time. We wanted to see what was ideal at that 230 or 240 day targeting window for harvest. 

Can you expand on the results?

 The re-implant program's gotten exceedingly popular just because of the need to cover more days. In this particular study, we had 2,300 heads with those three treatments. The steers had originated from the Kansas and Texas area. At the end of the day, the re-implant with the long duration, Choice followed by the Synovex ONE feed lot, gave us the best performance. Ten more pounds of hot carcass weight than just the normal Choice Plus. Fifteen more pounds of live weight was achieved. We improved our quality grade. We also picked up some points in terms of upper two-thirds choice and prime, about eight points of quality grade. 

We were able to show that extending those days of coverage with an implant program, making sure those cattle never ran out, added a performance and financial advantage for the customers. The delay program was not different in terms of performance, so that was  also a good option as well. The concern some customers have with that is if you delay, then they must come back through the chute at an additional time. So, it's three trips through the chute versus only two. Some operations can manage that, and that's a tool that can be in their toolbox, but others want to minimize the number of trips through the chute. 

A little more stress, a little more labor involved in that setup?

Yes. With implementing the Choice followed by the ONE feed lot, not only did we get maximized performance. We also improved operational efficiency with two trips through the chute instead of three. Those cattle come back through on day 80 to get their re-implant. They're a little bit lighter versus cattle that are coming back through day 120 or 150 that are a little bit bigger to fit through the chute. 80 days is just what we did in this study, but you could re-implant those cattle anywhere from day 60 up to day 120 per the label. 

How important is this kind of research for Zoetis and for feed yards that are feeding cattle longer than 200 days? 

That is a great question. It’s important because being one of the implant leaders in the industry, we want to provide as much information and support for our products as possible. There was this gap in between 200 day cattle and the long-fed cattle. We wanted a solution. We work a lot with nutritionists in the industry to find out what questions  they need answered. This was one of them. It's important to us, but it's also important to our customers to know how to best utilize these tools. We have a lot of tools in our toolbox, and some customers will choose tool A and some tool B. It just depends on which implant program is best for their operation and their production goals. 

What are the benefits of an implant program? 

Hormones are naturally occurring in all our bodies. When you are born, you're born with the same number of muscle fibers at seven or eight pounds as when you weigh 150 or 200 pounds. Hormones are how our body communicates, and they tell our muscle cells to grow larger. So, we're utilizing the same technology, the same pathways in cattle. We utilize growth using implants. This allows those muscle cells to grow larger. We can then feed them the same quantity of feed, the same input, same resources, but we get more pounds of beef. It's a great sustainability message. 

Implants, which were our first product, were approved in 1956. That was long before sustainability and those things were thought of. The cattle industry has been sustainable for many years, even decades, because we implement technologies that help make these cattle more efficient. Anytime we can do more with less is a great step in the right direction to improve our footprint, improving the sustainability of not only the cattle industry, but of the world. 

This is one tool that's being used across the industry to help with sustainability, right? 

Yes. There are tons of other options that help with improving efficiency and sustainability. Healthy animals are more productive animals. More productive animals are more sustainable. Whether you're talking about vaccines, parasites or implants, there are lots of tools. With genetic testing, especially for dairy, there's many ways that we can identify animals that are more productive, healthier and more sustainable. 

Does the US have any other research or added information related to growth implants? 

We continue to invest in this space. It's an area where we want to provide as much flexibility for our customers as possible. Over the last 12 months, we've had a couple of new approvals. Synovex Primer is 50 milligrams of trenbolone acetate (TBA) and seven milligrams estradiol benzoate. It's a lower dose combination implant. It was approved for dry lot production and for pasture. We're launching it here in the pasture setting, which was approved in January.

Zoetis offers three different options for pasture cattle. There’s choices for summer grass or small grains in the fall, some short and long duration options. If you have any questions, please make sure you can get in touch with a tech service or with your local sales representative. We can get you hooked up with what's best for your production goals. 

How does usage differ in different groups of cattle? 

The hormone concentration or the hormones in the different implants are similar, but we're able to adjust the concentration. We want to match the growing period of that animal with the right dose. A younger animal needs less stimulation. However, when those animals get older, they get less efficient later in the feeding period so we might use a little higher dose to stimulate the muscle growth that we talked about earlier. It's not always a brand new product. Sometimes it's figuring out a better way to use them and how we can help the customer to help the cattle in an ideal situation. 

Innovation isn’t always a new product, it is sometimes making effective changes, right?

Yes. A lot of our innovation is the support we give whether it's from our veterinarians, a nutritionist like me or our field force; doing things like ear checks,  helping the cowboy crews identify sick animals, how to do necropsies or things of that nature. A lot of the innovation and what Zoetis can help provide is more than a support standpoint versus having a new product every year. We'd love to have that but it's a tough space. There are many regulations in developing new products. One of the things we continue to work on is how we can better support our customers because if they can do a better job identifying a sick animal earlier, then it's more likely that the antibiotic of choice will be successful. If we get too late in some of those pools, it's harder for some of those antibiotics to work as they should.