Warm season pastures such as native grass or bermudagrass will be declining in forage quality in the hot dry days of August and September. Also these warm season grasses will be reaching plant maturity, which accelerates the decline in protein content.
Cow calf producers with fall-born replacement heifers should plan now to provide adequate protein supplement to aid the young heifers in their ability to digest the late summer, mature grasses.
Therefore, the young heifers must receive supplemental protein to continue to grow at the necessary pace of 1.3 to 1.5 pounds per head per day going into their first breeding season.
An economical solution would be to give these heifers 1.5 to 2 pounds of the protein supplement called Oklahoma Gold. This is an OSU-developed protein supplement scheme that consists of a high protein (38-45 percent) pellet that contains the label-recommended dosage of one of the ionophores.
Ionophores are feed additives (monensin or lasalocid) that improve feed utilization, inhibit coccidiosis, and enhance the onset of puberty in growing heifers.
Research from Texas A&M in the 1970s (Moseley, et al.) indicated that heifers receiving an ionophore reached puberty about 2 weeks earlier than counterparts that did not receive an ionophore. Therefore inclusion of the ionophore in the growing program should cause a few more heifers to be cycling early in the breeding season.
Very lightweight or very young, weaned heifers that need an added boost while still on late summer pasture may benefit more from the Oklahoma Super Gold supplementation program.
Super Gold consists of feeding 3 pounds per head per day of a 25 percent crude protein pellet. Once again, an ionophore is included at the proper dosage and will be beneficial to these young growing heifers.
These supplementation strategies were designed for efficiently improving gain for stocker cattle on summer pastures. 
—Glenn Selk is an Oklahoma State University Emeritus Extension animal scientist. Excerpts from Cow/Calf Corner e-newsletter.
