AMES, Iowa – Recent research as Iowa State University (ISU) has found that feeding OptaflexxTM (Ractopamine) to all cattle is more beneficial than feeding it only to the slow-gainers or lighter-weight cattle in a group. The study was designed to evaluate and demonstrate two management options for feeding Optaflexx in feedlots where cattle are topped out or sorted out of pens prior to harvest.
Optaflexx is a feed additive from Elanco Animal HealthTM that can add 10 to 15 pounds of carcass weight on cattle without increasing the amount of feed. It is described as a beta agonist that has a different mode of action than either implants or ionophores. This additive must be administered to cattle the last 28 to 56 days before harvest, and is designed to lower the production cost of cattle. It has recently been approved for use by the Food and Drug Administration (FDA).
Results showed that sorting cattle into market outcome groups prior to the last 28 days of feeding, as well as feeding Optaflexx to all of the cattle, is a viable alternative to only feeding Optaflexx to the ‘last draft’ to be marketed.
Iowa cattle feeders often sort market-ready cattle from pens and market the cattle in two or three groups, according to Dan Loy, ISU animal science professor. This ‘topping out’ of pens is a management technique that has existed since cattle were sorted to fill rail cars destined for Eastern markets. However, “to make the most efficient use of Optaflexx, it should be feed to all cattle in the group,” advises Loy.
"If producers can sort cattle early without affecting the production benefits of Optaflexx, it is certainly beneficial for them," Loy says.
Sorting the cattle early did not affect the behavior of the cattle in respect to the amount of feed they consumed, nor did it cause significant stress in reestablishing the social hierarchy of the pen, which was an initial concern, according to Loy.
For more information, visit the Activities and Research page at www.iowabeefcenter.org.
Rachel E. Martin, Iowa Beef Center, (515) 294-9124,