157 Effects of Monensin and Protein Type on Performance of Yearling Steers Grazing Smooth Brome. (7th May 2021)

• Record Type: Journal Article
• Authors: Carlson, Zachary E; Butterfield, Kylie; McPhillips, Levi J; Erickson, Galen E; MacDonald, James C
• Is Part Of: Journal of animal science. Volume 99(2021)Supplement 1
• Page Start: 122
• Page End: 123
• Publication Date: 2021-05-07
• Subjects: cattle -- grazing -- monensin -- rumen degradable protein -- rumen undegradable protein; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/skab054.203
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: A two-yr study was conducted to evaluate the effects of monensin on sparing ruminal degradable protein in yearling steers grazing smooth bromegrass pastures (n = 288, initial BW = 332 kg, SD = 7). Treatment design was a 2 x 3 factorial with the following factors: 1) 0 or 200 mg monensin/steer daily; 2) no protein supplement, 1.25 kg soybean meal (SBM) as a source of RDP, or 1.31 kg non-enzymatically browned SBM as a source of RUP. Steers receiving supplemental protein were provided isonitrogenous amounts equivalent to dried distillers grains plus solubles at 0.50% BW. Steers were weighed approximately every 34 d to adjusted the amount of protein supplement. There was no interaction (P > 0.41) of monensin by protein type for average daily gain (ADG). Rate of gain for steers supplemented monensin was not different (P = 0.26) from steers not supplemented monensin. However, monensin supplemented steers numerically gained 7.9% more than steers not provided monensin when no supplemental protein was provided. Compared to steers supplemented with no protein, supplementing RDP increased ADG by 0.19 kg/steer (P < 0.001). Likewise, RUP supplementation increased ADG by 0.24 kg/steer (P < 0.001) compared to steers supplemented no protein. Supplementing RUP increased ADG by 0.05 kg/steer (P < 0.001) compared to steers supplemented RDP. Supplementing protein, especially rumen undegradable protein, improved yearling steer rate of gain on smooth bromegrass pastures. Monensin supplementation did not improve rate of gain. These data do not support the protein-sparing effects of monensin for steers supplemented with RDP.