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Implanting Strategies for the Feedlot

April 7, 2015

Implanting cattle is a high return management practice if the proper implant is used at the proper time. Using implants can increase body weights, feed intake, and feed efficiency. The ROI from using implants can approach 30:1.


There are some fundamental things that need to be known about implants before a plan can be put together.

The days on the label are guidelines, and many of those guidelines were established by FDA testing many years ago when cattle were smaller framed and when average diet energy levels were lower. Most recommended days on the labels would be considered on the long end, but know that you also have some flexibility. Most feedlot implants could fit into a 70-120 window.

  1. Cattle will metabolize (use up) the implants based on two things, their body weight and the energy concentration of the diet. The smaller the calf is, and the lower the energy content of the diet is, the longer the implant will last. The larger the calf is, and the higher the energy content of the ration is, the faster the implant will get used up. For example, a Ralgro on a suckling calf may last 120-150 days, while that same Ralgro in a 600# steer on a feedlot ration will most likely last 45 days.
  2. Implants will consistently increase the performance of cattle, and they will consistently reduce the marbling score of cattle; this is because the implants increase muscle accretion without increasing the marbling in that muscle. 95% of the time (or more) the pounds gained to sell will have more value than the premiums received on higher marbling cattle that also weigh less. If you are selling cattle live, select implants with the highest levels of active ingredients to get the most weight gain. If you plan to sell cattle into a formula or grid, use the intermediate dose implants for the right balance of performance and carcass quality.
  3. Implants need to be fed, especially implants containing TBA. If the diet is too low in protein, or if intakes are restricted, the implants will not perform as expected and the marbling can be reduced even more than expected. Work with your consultant to be sure your diets are properly balanced.
  4. Implants need to be placed properly between the ribs in the ear without any crushing, balling, or spacing of the pellets. Good facilities that safely restrain the cattle, and good technique & sanitation by the implanter are very important. Many buller or stag issues can be traced back to improper implant application.



  1. Delayed implanting. This is typically done at the beginning for 3 reasons
    1. The implant status of incoming yearlings is often unknown, so the initial implant is delayed to avoid stacking on implants the yearlings may have received before.
    2. The nutrient density of the receiving and step up diets is lower than the finishing diets, so a TBA containing implant is delayed until the cattle are on a higher energy diet.
    3. In order to best fill the total days on feed, the very front end of the feeding period (where the feed efficiency is least likely to be affected) is left open so that the rest of the time the cattle are on feed they can have active implants when they are most needed.
  2. Stepping up implants. Many consultants recommend that implant strategies start with lower dose implants and each succeeding implant is higher in dose so that optimum performance is realized out of each implant and so that the implants best match the diet energy and the body weight of the cattle as time goes on.
  3. Terminal window. This is last 70-90 days on feed, and typically the place where the highest dose implant is used. This is the first number you need in order to calculate the combination of implants needed during the entire feeding period.
  4. Fill the days. Look at the expected days on feed for the group of cattle, and be sure that most if not all of the days have an active implant in the ear. If there is going to be time without an implant, make it at the front end (delay the initial implant). If you need to “stretch” an implant to fill the days, do it with the earliest implant that you can – the smaller cattle will be metabolizing the implant slower anyhow.



  1. Yearling steers, expected to be on feed for 180 days. Start with the terminal implant – 80-90 days for the last, higher dose implant. This leaves 90-100 days for the initial implant, so implant with a medium or intermediate dose implant on arrival.
  2. Larger calves, expected to be on feed for 210 days. Starting the with terminal implant window of 80-90 days, that leaves you with 120-130 days to fill. You can either implant on arrival with a medium dose implant and stretch it for the 120-130 days, or you can delay the initial implant 30 days so that you get 90 days on each implant.
  3. Normal calves, expected to be on feed for 240-270 days. Either way, figure your 90 days for the terminal implant, leaving you with 150 – 180 days. For the shorter day calves, you can delay the initial implant 30 days and then stretch it for 120 days to fill the 150 days. For the longer day calves, you could use two 90 day implants to fill the 180 remaining days, for a total of three implants.


Other notes:

  1. You could use a slow release, longer acting implant to replace two of the 90 day implants. Be sure the dosage is correct for your goals. For example; a Compudose that would last 150-180 days has the same effective dose as a single Synovex S that would last 90 days, while a Revalor X that would last 150-180 days would have the same dose as a Revalor IS plus a Revelor S which are each 90 day implants.
  2. Fed Holsteins naturally do not marble as well as beef breed cattle. As a result, if selling Holsteins into a formula or grid avoid full dose TBA containing implants so that you don’t lower the marbling too much.
  3. Steers and Heifers. Synovex Plus, Revalor 200, and Compudose can all be used on both steers and heifers – this can be helpful when looking for one implant to use on mixed pens.
  4. Ralgro in a feedlot implant strategy. Ralgro is very well liked as an implant – it was the first commercially available implant and is often considered to be the easiest implant to use. As stated earlier a Ralgro would typically be expected to last about 45 days in a feedlot situation; because of this Ralgro was commonly used to fill in the 40-50 gaps in some implant strategies, but now most consultants would recommend simply delaying the initial implant and to skip the use of Ralgro in this way. Ralgro continues to be an excellent implant for calves on cows and calves in a backgrounding situation. If you would like to use a Zeronal based implant for feedlot cattle, you can use the Ralgro Magnum.
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