Management of Optaflexx in Feedlots that Sort Cattle Prior to Market

  • W. Darrell Busby (Iowa State University)
  • Daniel D. Loy (Iowa State University)
  • Dallas L. Maxwell (Iowa State University)


One hundred and thirty five steers from were used in a study to compare strategies for managing Optaflexx in feedlots that sort cattle just prior to market. The pens were assigned to one of two Optaflexx management treatments. Two pens were each assigned to each treatment. The Optaflexx management treatments were: 1) Topped Out (TO), where half the cattle in each pen were sorted without being fed Optaflexx. The remaining cattle were fed Optaflexx for 28 days, or 2) Sorted Early (SE), where market timing decisions were made more than 28 days prior to the first marketing so that Optaflexx could be fed to all of the cattle. Feed consumption levels and patterns were not affected by sorting cattle early into market outcome groups. There were no differences in performance between the two sorting treatments. Cattle in the SE treatment had significantly larger ribeye areas. Based on the results of this study sorting cattle into market outcome groups prior to the last 28 days of feeding of the first group to be marketed so that Optaflexx can be fed to all of the cattle in the pen is a viable alternative to only feeding Optaflexx to the “last draft” to be marketed.

Keywords: ASL R2074

How to Cite:

Busby, W. D. & Loy, D. D. & Maxwell, D. L., (2006) “Management of Optaflexx in Feedlots that Sort Cattle Prior to Market”, Iowa State University Animal Industry Report 3(1). doi:

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Published on
01 Jan 2006
Peer Reviewed