“Generally, the response is similar to that of beef animals,” he says.
The use of technologies such as implants improves muscle shape, yield and carcass dressing percent. But that doesn’t mean making decisions about implants in Holstein steers is easy. “The problem is that there are about 34 implants on the market, and then there is the confusion of how to develop a program that works best for the situation,” he says. Implants differ in delivery systems, payout duration, active ingredients and potency.
Depending on the implant and the age and sex of the animal, implants will improve growth rate from 10% to 20% and decrease the cost of beef production by 5% to 10%, Loy says.
Implants use hormones to change what happens to the nutrients cattle consume and encourages muscle growth over fat deposition. Because muscle is more efficiently produced than fat, the animal grows faster with less feed consumed, he explains.
Implants are usually small pellets placed under the skin in the animal’s ear which dissolve over a 100- to 150-day period. (The ear is used because they do not enter the food supply.)
The active ingredients – most of which are naturally occurring hormones – are either estrogens or androgens. The estrogens can be natural, synthetic or plant-based, and the androgens can be natural or synthetic. The synthetic androgen used in implants (trenbolone acetate) has fewer of the negative aggressive male behavior effects and more of the muscle-enhancing effects compared to natural androgens.
Implants generally are either an androgen and estrogen combination or just estrogen, with the estrogen-only implants used on younger animals and the more potent combination implants used to finish animals.
Holstein steers consume 8%-15% more feed than beef breeds for equivalent weight gain and have an 8%-12% higher maintenance energy requirement than beef breeds. The different energy requirements for Holstein steers does not change the way implants should be used, with the exception that they are on feed longer, so longer-lasting implants may be needed.
The biology of a Holstein steer is different from that of a beef animal. Holsteins have a lower muscle-to-bone ratio, and they differ in fat distribution from beef breeds. “Holsteins have more internal and seam fat, and less external fat,” Loy says.
“The most important implant is the last implant before you market the cattle,” Loy says. For the cow-calf producer, the most valuable one is the calfhood implant. For a feedlot producer, that is the terminal implant. The date of administering the last implant is based on counting backward from the target marketing date.
Some producers use an initial implant in the feeding period and a second for finishing the animal. What works best on a given operation should be regularly reviewed, preferably after each group is marketed but at least annually, as feed and cattle prices can impact the return. Typically, higher feed prices give a higher return to the investment of using implants, Loy says.
He suggests taking a look at the strategic marketing goals of what you want to accomplish with this particular group of animals, and to start at the end because that is when the cattle are growing the fastest, and the response to implants is on a percentage basis.
For example, if feed costs are low, you might be more aggressive and use a higher potency in order to maximize the impact on costs of production. If high carcass quality is your end goal, then perhaps be more conservative with dosage at the end.
Those seeking more information about implants can look up the implant fact sheet available at the iowabeefcenter.org, under the “Fact Sheets/Publications” tab, then “Feedlot Management.” 
—Excerpted due to space limitations. Kelli Boylen is a freelancer in northeast Iowa.
