Using Growth Implants in Yearling Stockers

July 4, 2016 03:32 PM

By: Ken Olson, South Dakota State University Extension 

Implants have been an effective tool to economically improve rate of gain and feed conversion in growing cattle for decades. Generally, implants are expected to increase rate of gain by 10 to 20% for yearling cattle on grass. Because implants are inexpensive, this can create a return on investment exceeding 20 to 1, depending of course on cattle prices relative to implant cost.

Implants contain naturally occurring or synthetic analogs of steroidal hormones, including estradiol, progesterone, and/or testosterone. These hormones in turn cause an increase in growth hormone in the animal, contributing to the improved rate of gain. A variety of implant products are available on the market that contain these active ingredients, either individually or in various combinations. These products also vary in the daily dosage (concentration) as well as the effective lifespan of active ingredients (payout).

Choosing the best implant

Choosing the best implant from the wide array of available products is key to maximizing the “bang for the buck” without any negative side effects. The first consideration is the potency of the implant. In general, implants are grouped as low, moderate, and high potency. This is based on which combination of active ingredients is used and their daily dosage. In general, use only implants that are approved for grazing cattle; these are the low- and moderate-potency implants. The high-potency implants are approved for use only in confined feedlot cattle. A major reason for this is that potency has to correspond with energy level in the diet. High-potency implants are intended for use in cattle on high-energy finishing diets in the feedlot. Grazed forage does not have the energy content to match well these high-potency products.

Side effects and management considerations

The major negative side effect attributed to implants is their potential to reduce marbling and therefore USDA Quality Grade in cattle. Research has clearly shown that implants do not reduce marbling if adequate energy is being consumed that allows intramuscular fat to be deposited at the increased pace of overall gain driven by the implant.

On the other hand, green grass from late spring through mid-summer provides adequate energy to support marbling deposition needed for the gain increase expected from moderate-potency implants. This means that a low-potency implant, although approved for use in grazing cattle, may not provide the best bang for the buck during the early portion of the grazing season when forage quality and cattle gains are expected to be highest. However, as summer advances and grass quality decreases as it matures, energy intake may decline to a point that does not support the capacity of a moderate-potency implant.

This challenge can be addressed by considering the lifespan of various implants. We often consider the lifespan of the implant relative to the expected length of the grazing season. For example, if the intent is to graze from mid-May to early October (about 135 days), many implant products pay out in 100 days or less. This leaves a producer with 3 possible options for the remainder of the grazing season: The first option is to gather the cattle and re-implant. This option if probably the least desirable for several reasons. First, it involves the cost, time, and effort to buy another round of implants and then gather and work the cattle. Additionally, as mentioned above, this is a period of declining gains in cattle, so the expected response to the re-implant will decline in direct proportion, and the possibility of negative impact on marbling exists unless a low-dose implant is used. Finally, most of the remaining life of this re-implant will last beyond the grazing period. This is ineffective from the grazing standpoint and may interfere with subsequent feedlot implant goals. Another option is to use an extended-life implant. Some of these can have a life as long as 400 days. This option ensures active ingredient payout at least as long as the grazing season. The third option would be to leave the cattle without implant coverage late in the grazing period. This may be the best option because of declining forage energy content and the potential negative effect on marbling fat deposition during late summer and fall.

Potential economic advantage

Based on these options for an implant strategy, consider the potential economic advantage of implanting yearling stocker cattle. For example, assume we start the grazing season with some 600 lbs. yearling steers intended to graze for 130 days. During the first 100 days of the grazing season we would expect 2.5 lb. of average daily gain (ADG) without implants. We choose a moderate-potency implant that is expected to improve ADG by 15% over about 100 days. The enhanced ADG will be 2.88 lb., leading to an additional 38 lb. of growth. Using the Beef Basis Forecasting Tool, the projected sale value in late September of this additional gain will be $51.77 per steer. If the implant costs $1.35 per head, the return on investment is projected at 38:1 (assuming steers are implanted when being worked before turnout to grass so there are no additional costs of implanting).

Other considerations

An alternative would be to enroll the cattle in a NHTC (Non-Hormone Treated Cattle) program that would provide a price premium for leaving them un-implanted. In this case, the NHTC premium would have to be greater than the ~$50 net value from using implants.

A word of caution: proper implanting procedures are critical to ensure full effectiveness of the implant to accomplish this economic advantage. First, implant placement is important. The implant should be inserted so it is midway between the base and tip of the ear, and midway between the two main cartilage ribs of the ear. It should be inserted under the skin (subcutaneous) and not buried in the cartilage of the ear. Additionally, the needle on the implant gun should be kept clean and sharp. The needle should be sanitized in a disinfecting solution between using it in each animal. Wiping the needle across a sponge soaked in the disinfectant solution can effectively accomplish this. If microbial contamination is inserted with the implant, an infection can occur that will cause an abscess to form around the implant, walling it off from absorption into the animal’s bloodstream. This will render the implant completely ineffective.

Using an effective strategy and technique, implanting yearling stocker cattle going to grass can be an effective and nearly guaranteed avenue to add value.

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