Date of Award

5-2009

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Plant and Environmental Science

Advisor

Andrae, John A

Committee Member

Duckett , Susan K

Committee Member

Pinkerton , Bruce W

Abstract

The objective of this study was to evaluate how forages grazed during the summer months alter live animal performance, carcass quality, consumer acceptability and fatty acid composition in finishing beef cattle. Angus-cross steers (n=60) were finished on alfalfa (AL), bermudagrass (BG), chicory (CH), cowpea (CO), and pearl millet (PM) during this two year trial. Using a complete randomized block design, ten 2-ha paddocks were blocked and assigned to forage species (2 reps per species). Each year, steers (n=3) were randomly assigned to paddocks and grazing began when adequate forage growth for individual species was present. Put and take grazing techniques were utilized. Steers were slaughtered when sufficient forage mass for individual forage species was no longer present to support animal gains or when average steer weight exceeded 568 kg. Data were analyzed using PROC MIXED of SAS. Average daily gains were higher for alfalfa (AL) than bermudagrass (BG), cowpea (CO), and pearl millet (PM) treatments, whereas chicory (CH) ADG were higher (P = 0.02) than BG and PM. Dressing percentages were greater (P = 0.01) for AL and CO than BG and PM, while CH was higher than BG. Cowpea carcasses had the highest (P < 0.05) quality grades and marbling scores. A blind consumer taste panel rated beef from AL, CO and PM higher (P < 0.01) in overall palatability than CH and BG. Postmortem aging decreased (P < 0.01) Warner-Bratzler shear force. Shear force scores were lower (P = 0.05) for AL and CO than BG and CH. CLA cis-9, trans-11 concentration was greater (P = 0.05) in BG and PM than other treatments. Chicory and CO treatments had greater concentrations of linolenic acid than other treatments, whereas AL was higher in concentration than PM (P < 0.01). Stearic acid was higher (P = 0.02) in concentration for CO than CH, PM, and AL. Stearic acid concentration was higher (P = 0.02) in BG than PM and AL, and CH was higher than AL.

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