Date of Award

12-2014

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

John C. Waller

Committee Members

Gary E. Bates, Craig A. Harper, Patrick D. Keyser

Abstract

Early season (ES) and full season (FS) grazing strategies were used to evaluate performance of stocker steers grazing native warm-season grasses (NWSG) in 2010, 2011 and 2012 in two experiments. Experiment one was conducted at the Research and Education Center (REC) at Ames Plantation near Grand Junction and experiment two was conducted at Highland Rim REC near Springfield in which Angus and Angus cross steers (268±25kg) were used in completely randomized design with three forage treatments: 1) switchgrass (Panicum virgatum L.); 2) a combination of big bluestem (Andropogon gerardii Vitman) and indiangrass (Sorghastrum nutans); and 3) eastern gamagrass (Tripsacum dactyloides). Stands of switchgrass (SG), big bluestem and indiangrass (BB/IG) and eastern gamagrass (EG) were 3 yr old (28%) or 4 yr old. Before and after grazing NWSG pastures all steers were fed a high fiber filler diet for 4 d with individual BW taken in the early AM each day and the average BW for the last 2 d was used for initial and final BW for the grazing period. Four steers (testers) were allotted to 1.2-ha paddocks with three replications per treatment. Additional steers were used in a put-and-take manner to keep forage in a vegetative state. Steers had free choice access to pasture, water, mineral, and shade. Data were analyzed using the MIXED procedure of SAS. Experiment one least square means for ADG of ES steers grazing BB/IG and SG differed from EG (P < 0.05) with ADG of 1.23, 1.14 and 0.84 kg/d respectively. Least square means for ADG of FS steers grazing BB/IG differed from SG and EG (P < 0.05) with ADG of 0.82, 0.56 and 0.48 kg/d respectively. Experiment two least square means for ADG of ES steers grazing BB/IG differed from SG (P < 0.05) with ADG of 1.09 and 0.88 kg/d respectively. Least square means for ADG of FS steers grazing BB/IG differed from SG (P < 0.05) with ADG of 0.96 and 0.79 kg/d respectively. The results of these two grazing experiments demonstrate the ability of NWSG to provide adequate summer performance for cattle grazing in the mid-south.

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