Growth implants must be correctly timed or marbling, grade lessened


WOOSTER, Ohio – Implants can negatively affect quality, if you let them.
Growth implants are commonly used in the cattle industry with little regard to how they influence marbling, the “taste fat,” said Gary Fike, feedlot specialist for Certified Angus Beef LLC.
“For every dollar invested in an implant, the return could be more than $6 in increased weight and efficiency in today’s marketplace,” he said.
“Most producers can’t afford to leave that kind of money on the table, but if the implants aren’t used properly, they could cost significant dollars in lost grid premiums.”
Nutrient shift. Implants shift nutrient use to lean muscle, rather than marbling or intramuscular fat, which decreases quality grades.
Since 1995, packers have paid more than $200 million in grid premiums for cattle meeting the Certified Angus Beef brand specifications.
Those who want these bonuses must pay attention to management decisions that impact the end meat product.
“The degree to which implants suppress marbling can be minimized,” Fike said, “if used judiciously and in harmony with nutrition, timing and age of the cattle.”
He analyzed the Certified Angus Beef database that tracks cattle fed in nearly 70 partner feedlots across the country.
The Feedlot Licensing Program information shows that both the number and potency of the implants used affect quality grade.
Best of both. Fike asked, “Why not try to reap the economic benefits of the implant on growth and performance and couple that with quality premiums?”
Looking at 12,000 rows of detailed carcass records from the 2005 dataset, he divided cattle into four Certified Angus Beef acceptance rate groups: 0 percent to 9.9 percent, 10 percent to 19.9 percent, 20 percent to 29.9 percent, and over 30 percent Certified Angus Beef.
Feeders submit the number of times cattle were implanted and the brand name of the implant used.
Cattle in the over 30 percent certified group were implanted 0.91 times – significantly fewer times than all other acceptance rate groups.
The average on all 2005 cattle was 1.3 times, and non-implanted cattle achieved 37 percent acceptance.
Potency. Chris Reinhardt, Extension feedlot specialist at Kansas State University, ranked implant potency by active ingredient.
Potency scores ranged from 1 for “low” to 5 for “very high.”
Averages were figured for each lot of cattle.
The mean implant potency score for the top Certified Angus Beef group was 1.88, significantly lower than for the other three groups.
Fike said the lower acceptance groups had been implanted with much more aggressive products.
“The acceptance rates were most affected when average potency score exceeded three.”
Overall implant values were assigned to lots by multiplying average potency by the number of times implanted. The results mirrored the implant potency scores.
Whole story. “This doesn’t tell the entire story,” he said.
“Whether the timing of the implant matches nutrition level can make or break quality grade.”
An implant containing both trenbolone acetate and estrogen can be beneficial to performance and not affect quality grade significantly, Fike said. That’s if it is given at the right time with a nutrition program that matches the dose.
On the other hand, aggressive use of high-dose implants used early in life – immediately pre- or post-weaning – can “wreck” marbling, he explained.
That’s especially true if the diet is high in roughage and low in energy.
“If a producer holds off on implanting them until the cattle are on high-energy feed, the depression of marbling will be much less,” Fike said.


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