May 5, 2000

Implants are one of the most effective, and often overlooked, tools for promoting weight gain, according to Dr. Todd R. Thrift, Extension livestock specialist—a featured speaker at the Beef Field Day hosted by the Texas Agricultural Extension Research Center at Overton late last month. Thrift told producers that implanting suckling calves and stocker cattle offers one of the highest benefit-to-cost ratios, but cautioned that it is important to do it right.

"To avoid infection, make sure the ear surface, the implant applicator needle and your hands are clean," Thrift told onlookers during a cattleworking demonstration offered during the field day.

He recommended using trays provided by implant companies, or perhaps a modified paint roller tray, at chuteside as a place to rest the implant applicator when not in use, and to clean the applicator needle.

"Before administering the implant, use a sponge soaked in disinfectant to remove manure and other foreign material from the ear surface," he said, indicating a preference for commercial disinfectants over bleach solutions used by some cattlemen. "You can also use the sponge to clean the applicator needle."

Site location of the implant is also important, Thrift noted, advising producers to place the implant under the skin on the backside of the middle third of the ear (implanting at any other location violates federal law).

Thrift showed producers several types of applicator guns and explained the importance of knowing how to use them to avoid crushing the implant.

"Crushing the implant is a common mistake. You may want to back the needle up a little to avoid that. And you want to make sure you don’t bunch or waste the implant pellets. A pellet on the ground won’t do the calf any good," he said, stressing the importance of using a needle that is sharp and free of spurs.

Afterwards, apply pressure on the site entry, to help the wound close.

A hand-out from Thrift said implanting suckling calves once with zeranol or estradiol-progesterone type implants will increase daily weight gains an average of 0.10 pound per day for steer calves and 0.12 pound per day for heifer calves (taken from 1997 trials conducted by Glenn Selk at the Oklahoma Agricultural Experiment Station). Implus-C (Calf-oid), Component-C, Compudose, Encore, Ralgro, and Synovex-C are labeled for suckling steers and heifers. Component-S, Component-H, Implus-S, Implus-H, Synovex-S, and Synovex-H can also be used in sucking calves but are recommended for calves weighing over 400 pounds (refer to product labeling for specific instructions/restrictions).

"If you plan to keep heifers for replacement, do not implant them," said Thrift, noting reproductive concerns. "It provides no benefits."

Currently, Synovex-C, Component-C and Ralgro are the only implants labeled for use in replacement heifer calves. Use is restricted to heifers older than 30 days for Ralgro and 45 days for Synovex-C and Component-C.

There is some evidence that implanting all the heifer calves once, between two months of age and weaning, does not significantly affect reproduction in heifer calves that may later be selected for replacements. And it will result in heavier weaning weights for the remaining heifer calves.

"No implants are labeled for use in bull calves intended for future use as herd sires," said Thrift.

Implants can suppress testicular development and reduce libido and semen quality, he explained.

According to 1997 trials at the Oklahoma Agricultural Experiment Station, looking at the impact of implants on performance and carcass value of beef cattle, a single implant will increase weight gain 8 to 18 percent, or 15 to 40 pounds, during the grazing season. The studies showed that if the grazing season is more than 100 to 120 days and the plane of nutrition is adequate, reimplanting or using an implant with a longer release period stimulates additional weight gain.

Implus-C (Calf-oid), Component-C, and Synovex-C are recommended for calves weighing less than 400 pounds and can be used with lightweight stocker cattle.

Thrift said reimplanting, or administering a second implant at some interval after the first implant, improves performance, provided the cattle are receiving adequate nutrition.

"I don’t know that I would bring the cattle up specifically for a second implant, but if you’re running them through the chute for other reasons, it would be worth implanting them again," the livestock specialist suggested.

F. Ted McCollum III, Extension beef cattle specialist at Amarillo, said an implant releases, or "pays out," compound for up to 70 days.

"Although the implant releases active compound over an extended period, at some point the quantity of active ingredient released declines to a level that does not stimulate performance adequately," McCollum explained. "Therefore, the recommended reimplanting interval for each implant is shorter than the estimated payout."

McCollum further noted that a good rule of thumb for reimplanting the cattle is to time it about 30 days less than the estimated payout.