Implants for Feedlot Cattle I - SDSU Implant Calculator Back »

This article was written by Ben Holland, former SDSU Extension Beef Feedlot Specialist.


Growth promoting implants have long been among the most powerful technologies available for improving gain, efficiency, and final weight of feedlot cattle.  Years of research is available that show implants, are safe, effective, and, when used appropriately, have only minimal impacts on quality grade.   Given today’s high input prices, the economic benefit of using implants is greater than ever. 

Recently, Dr. Robbi Pritchard, Distinguished Professor at SDSU, developed a computer implant calculator that allows users to compare implant programs for specific classes of cattle and economic conditions.  In the following example, we’ll use the implant calculator to demonstrate the value of implanting some yearling steers.  The inputs for cattle performance and grade distribution used in this example are: Start wt, 866 lb; days on feed, 110; ADG, 3.18; DM, 24.3; ration cost, $265/ton; and “Average” cattle quality.  The grid prices are $172/cwt base, $8 Prime, $4 upper 2/3 Choice, -$7 Select, and -$16 No roll. 

On the Implant screen, choices are based on implant potency, and up to three implant strategies can be selected.  Let’s consider a common strategy for this class of cattle, such as using a single Revalor-S implant.  Commercially available implants of each potency are shown on the right of the screen and are available here.  We find that Revalor-S is a high potency implant. 

When looking at the output, using the implant increased ADG 22%, DMI 4.9%, and finish weight 6.3%.  It also improved feed conversion ratio 14%, resulting in a lower cost of gain.  However, it also reduced the percentage of carcasses grading Choice or better 10 percentage points.  Based on the pricing grid we used, the value of the extra weight more than offset the cost of the lower quality grade – the implanted animals were worth $92.78 more than non-implanted animals.  A couple of things to point out when using the calculator:

  1. As in any calculator, this application can only project outputs that are as good as the data entered, and the user inputs for cattle performance are based on non-implanted cattle.  This can be easy to estimate based on historical records for producers who have not been implanting.  However, for producers that have implanted for years, it is not so easy.  The alternative would be to change the inputs until cattle performance is as expected when using a known implant program. 
  2. All of the projections are based on Yield Grade 3.0 carcasses.  Cattle will reach a YG of 3.0 after the same days on feed, whether they have been implanted or not.  The primary effect of an implant is to increase the frame size of cattle, which brings us to the point of carcass weight discounts.  This calculator does not account for carcass weight discounts when calculating carcass values and users should be cognizant of how implant strategies might affect carcass weight.

The SDSU Implant Calculator can be a beneficial tool when selecting implant protocols for your cattle this fall.  It can be used to compare different implant strategies with multiple inputs and scenarios.  Next time, we’ll look at implant and reimplant strategies for longer day cattle.

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