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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #345655

Research Project: Develop Improved Plant Genetic Resources to Enhance Pasture and Rangeland Productivity in the Semiarid Regions of the Western U.S.

Location: Forage and Range Research

Title: Binary mixtures of alfalfa and birdsfoot trefoil with tall fescue: Herbage traits associated with the improved growth performance of beef steers

Author
item Waldron, Blair
item BINGHAM, TROY - Utah State University
item CREECH, J. - Utah State University
item Peel, Michael
item MILLER, RHONDA - Utah State University
item Jensen, Kevin
item ZOBELL, DALE - Utah State University
item EUN, JONG-SU - Utah State University
item SNYDER, DONALD - Utah State University
item HEATON, KEVIN - Utah State University

Submitted to: Grassland Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2019
Publication Date: 4/1/2020
Citation: Waldron, B.L., Bingham, T.J., Creech, J.E., Peel, M., Miller, R., Jensen, K.B., ZoBell, D.R., Eun, J., Snyder, D., Heaton, K. 2020. Binary mixtures of alfalfa and birdsfoot trefoil with tall fescue: Herbage traits associated with the improved growth performance of beef steers. Grassland Science. 66(2):74-78. https://doi.org/10.1111/grs.12257.
DOI: https://doi.org/10.1111/grs.12257

Interpretive Summary: High nitrogen (N) fertilizer costs and increased environmental stewardship have renewed interest in grass-legume pastures, and past research was not indicative of the productive, irrigated, rotational stocked pastures common in the western USA. This research compared herbage mass and nutritive value, steer weight gain, and economics of tall fescue-alfalfa (TF+ALF) and tall fescue-birdsfoot trefoil (TF+BFT) mixtures, to tall fescue with (TF+N) and without N fertilizer (TF-N). Pastures were established in Lewiston, Utah, USA, and rotationally stocked (28-day cycles) by Angus beef steers for 112 days in 2012 and 2013. Herbage samples were collected prior to each 7-day stocking period and analyzed for mass and nutritive value. Steers were weighed each 28-day rotation cycle and cumulative average daily gain (ADG) calculated. Steer ADG was greatest for TF+BFT (0.73 kg d-1), followed by TF+ALF (0.67 kg d-1), TF+N (0.61 kg d-1), and TF-N (0.40 kg d-1). Analysis indicated that small differences in energy, digestibility, and fiber had the greatest influence on ADG, but other variables affecting ADG included legume content, herbage mass, and BFT content. Tall fescue-legume mixtures had 29 to 33% legume content, and more favorable energy and fiber concentrations than grass monocultures. Herbage mass was greatest (p <0.05) for TF+N (2955 kg ha-1), followed closely by TF+BFT (2741 kg ha-1) and TF+ALF (2623 kg ha-1). This study showed that TF+BFT and TF+ALF pastures had better nutritive value, and nearly equivalent herbage mass TF+N, resulting in greater steer weight gains without the cost of fertilizer. Results also sugggested that steer gains can be further increased by minor improvements in the value-added herbage traits, energy and digestibility.

Technical Abstract: High nitrogen (N) fertilizer costs and increased environmental stewartship have renewed interest in grass-legume pastures, and past research was not indicative of the productive, irrigated, rotational stocked pastures common in the western USA. This research compared herbage mass and nutritive value, steer weight gain, and economics of tall fescue-alfalfa [TF+ALF, Lolium arundinaceum (Schreb.) Darbysh., Medicago sativa L.], and tall fescue-birdsfoot trefoil (TF+BFT, Lotus corniculatus L.) mixtures, to tall fescue with (TF+N) and without N fertilizer (TF-N). Multivariate analysis examined which herbage variables primarily influenced steer performance. Pastures were established in Lewiston, Utah, USA, and rotationally stocked (28-day cycles) by Angus beef steers for 112 days in 2012 and 2013. Herbage samples were collected prior to each 7-day stocking period and analyzed for mass and nutritive value. Steers were weighed each 28-day rotation cycle and cumulative average daily gain (ADG) calculated. Steer performance differed (p < 0.05) amongst treatments with ADG greatest for TF+BFT (0.73 kg d-1), followed by TF+ALF (0.67 kg d-1), TF+N (0.61 kg d-1), and TF-N (0.40 kg d-1). Principal component analysis indicated that small differences in energy, digestibility, and fiber had the greatest influence on ADG. Other variables affecting ADG were legume content, herbage mass, and BFT content. Tall fescue-legume mixtures had 29 to 33% legume content, and more (p <0.05) favorable energy and fiber concentrations than grass monocultures. Whereas, herbage mass was greatest (p <0.05) for TF+N (2955 kg ha-1), followed closely by TF+BFT (2741 kg ha-1) and TF+ALF (2623 kg ha-1). This study showed that TF+BFT and TF+ALF pastures had better nutritive value, and nearly equivalent herbage mass as TF+N, resulting in greater steer weight gains without the cost of fertilizer. Results also suggested that steer gains can be further increased by minor improvements in the value-added herbage traits, energy and digestibility.