Effects of Monensin and Protein Type on Performance of Yearling Steers Grazing Smooth Bromegrass Pastures

Authors

Z. E. Carlson, University of Nebraska-Lincoln
K. Butterfield, University of Nebraska-LincolnFollow
Levi McPhillips, University of Nebraska-LincolnFollow
Galen E. Erickson, University of Nebraska-LincolnFollow
M. E. Drewnoski, University of Nebraska-LincolnFollow
J. C. MacDonald, West Texas A&M UniversityFollow

Date of this Version

2021

Citation

Published in 2021 Nebraska Beef Cattle Report, University of Nebraska Extension Publication MP110

Comments

Used by permission

Abstract

Summary with Implications

Two-year study evaluated the effects of monensin on protein type, either rumen degradable or rumen undegradable, with yearling steers grazing smooth bromegrass pastures. Steers were supplemented soybean meal (rumen degradable protein) or nonenzymatically browned soybean meal (rumen undegradable protein) at isonitrogenous levels to dried distillers grains plus solubles provided at 0.50% BW. Likewise, steers were provided either zero or 200 mg/hd/d of monensin for a total of six treatments with a 2 × 3 (no protein, RDP, or RUP) factorial design. There was no interaction of monensin by protein type. Providing monensin to grazing yearlings did not improve ADG; however, monensin numerically improved steers daily gain by 7.64% when no protein supplement was provided. Previous research has demonstrated monensin supplementation in yearling grazing systems has improved rate of gain, though the improvement may be minimal. Both rumen degradable and rumen undegradable protein types improved daily gain by 31.15% compared to no protein supplement. Providing a rumen undegradable protein supplement improved daily gain by 5.63% compared to rumen degradable protein supplement. Therefore, providing protein, and especially a rumen undegradable protein, improved yearling steer performance on smooth bromegrass pastures.