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Stocker Cattle| May 2012

Stocker Cattle


By Lorie Woodward Cantu

Editor's Note: This is the fifth installment in a 12-part series on stocker cattle management. This series has been created in partnership with Chris McClure, Gold Standard Labs (, a lab services company based in Hereford that specializes in BVD-PI testing and blood pregnancy tests; and Danna Schwenk and Karla Whitmore, CattleXpert Management Software (, a software company based in Elkhorn, Neb., that specializes in feedlot and stocker management applications.

Over the past 40 years, growth-promoting implants have become standard tools in the cattle business. Like all tools, though, implants have to be used as they were designed to get the job done.

"Implants are tools that help an operator maximize gain in cattle that are still growing, but implants are not ‘silver bullets,' " says Dr. Dan Stafford, the owner and veterinarian at the Shiner Animal Hospital in Shiner. Stafford's clientele includes stocker operations and feedlots. "Implants can enhance performance, but only if the cattle are healthy and have adequate nutrition. An operator cannot use an implant to overcome poor feed, health or genetics."

Growth promoting implants are pellets that are implanted under the skin of the ear. There are approximately 15 major brands offered. They are available in 3 broad classes: for calves older than 45 days, growing or stocker cattle, and finishing or feeder cattle. Because implants interact with the production of hormones, they are not recommended for breeding animals. Older cattle, such as yearlings, tend to have the greatest response to implants because physiologically they are depositing lean tissue at a high rate.

The first implants to become available were estrogenic agents, which increase the levels of somatotropin and insulin-like growth-factor-1, improving the way the cattle metabolize and use nutrients to enhance growth. These products improved average daily gain 5 to 10 percent and feed efficiency 5 percent to 15 percent.

In 1987, trenbolone acetate, a tissue-building agent, was approved for use. It has an additive effect with the estrogenic compounds, enhancing muscle growth and adding another 2 to 3 percent to feed efficiency and 3 to 5 percent to the daily gains.

"The benefits of an implant regimen are difficult to see with the naked eye, but are realized in pounds of beef marketed and sold," says Stafford, who also owns and operates South Texas Consultation and Ring Ranch.

Early on implants, in some cases, negatively impacted quality grade, but because the agents have been refined, that is no longer a major concern, he says. Recent experience has shown that the weight gains clearly offset any slight impacts on marbling. It is estimated that each implant can add between 20 and 40 pounds to an animal, he says. Of course, to achieve the maximum gain every factor in the production equation — nutrition, health, genetics and weather — must be optimum, he says.

Operators should consult their veterinarian, nutritionist and animal health company representative to help develop an implant schedule and choose the product that best fits their operation, Stafford says.

Today's major brands of implants offer different combinations of estrogenic and/or androgenic agents. Implants have become so refined that they are now almost designer products, meaning that certain implants will better meet the needs of specific sets of cattle.

"My advice for operators is to get all the information they can to ensure they've made the best match possible between the implant and the cattle," Stafford says.

He also suggested that stocker operators talk to the managers of the feedlot for which their cattle are destined. In his experience, it can be worth a premium to create an implant protocol that complements what the feedlot will be doing.

Research shows that it is important to finish the feeding period with the most potent implant selected for the implanting program; therefore, if a combination trenobolone implant is selected as the first feeder implant it should be used in subsequent implants. By the same token, if an estrogenic implant without trenobolone is selected as the first implant, a similar product or an estrogenic-trenobolone implant can be selected for the subsequent implants.

"The key is using the proper implant at the right time," Stafford says.

Timing is another consideration. Each implant has a period of efficacy. For the growing/stocker implants, that is usually 90 to 120 days. Initially after implantation, hormones are rapidly released. The level of growth promotant will fall off after a few days, but will remain above an effective threshold for differing amounts of time depending on the implant's pharmaceutical design.

"Stocker operators needs to be aware of how long the implant is going to work and be prepared to re-implant if they are holding the cattle for a longer period of time," Stafford says. The re-implantation should occur before the level of implant hormones dip below the threshold. To save on labor costs and avoid additional handling, the initial implants can be inserted when the cattle are received and undergoing their initial processing.

To ensure the implants perform as they should, it is imperative that the working crews are trained on proper implant technique and sanitation.

"I spend a lot of time standing beside a chute watching different crews conduct their business — and not all of them do it right," Stafford says. "It's important that the implants are put in the proper location, using sharp, clean needles and the proper insertion technique."

The only approved location for an implant is the middle third of the backside of the ear. Because ears are inedible and discarded during processing, this location reduces any food supply risk. No other location is acceptable.

"Implants are governed by the FDA," Stafford says. "When used properly, they are safe and effective. It's important that operators follow manufacturers' instructions, so that the industry can continue to enjoy the production advantages they offer."

Improper implanting techniques are also an economic concern because of associated performance loss, he says.

"The stocker implants average $4 a piece, so if a significant number of implants are getting messed up, then you're wasting money on top of missing out on the additional gain," Stafford says.

Defects resulting from improper implanting techniques include abscesses, expelled implants, cartilage embedment, crushed pellets, missing pellets and bunched pellets.

Abscesses are a major concern, but can be controlled with proper sanitation. The primary sanitation objectives are manually removing dirt and manure from the implant area, and then treating the clean site with a disinfectant to kill bacteria. Implants can be rendered partially or totally ineffective when bacteria, many of which come from manure, are carried into the injection site by the needle. The bacteria grow and multiply within the implantation site causing an infection and abscess. Abscesses can "eject" all of the implant pellets from the site, causing the cattle to perform as if they've never been given a growth implant.

"When used correctly, growth implants are one of the most effective methods of enhancing weight gain and its efficiency," Stafford says. "Implants can help stocker operators get the job of producing beef done and done well."

"Stocker Cattle: Implants" is from the May 2012 issue of The Cattlemen magazine.