Document Type

Thesis - Open Access

Award Date

2024

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Amanda Blair

Abstract

The objective of this thesis was to determine the influence of an oregano-based essential oil (OEO; By-O-Reg+ Beef), on growth performance, carcass traits, and meat quality of beef steers finished in an all-natural program. Yearling steers were allotted to 16 pens (n = 8 pens per treatment, 8 steers per pen). Treatments included: 1) control (CON) fed no oregano-based essential oil and 2) group fed 4 g/steer daily of By-O-Reg+ Beef. Steers were harvested on day 149 of the feeding period. Standard carcass data was collected and instrumental color (L*, a*, b*) was recorded. Strip loins were collected from a subsample of carcasses (n = 62; 4 animals closest to mean live body weight per pen). Purge loss and pH were recorded and strip loins were fabricated into steaks. One steak was utilized for proximate composition analysis. Four steaks were assigned to age for 4, 7, 14 or 21 days for Warner-Bratzler Shear Force (WBSF) analysis. One steak was overwrapped with oxygen permeable film and placed in simulated retail display for 10 days for evaluation of objective color (L*, a*, b*), subjective color, and discoloration. Three steaks were aged for 4, 7, or 10 days for analysis of lipid oxidation. Treatment did not influence (P > 0.05) growth performance, carcass traits, liver score, initial color, purge loss, or proximate composition. Striploins from the OEO treatment had increased pH values (P = 0.0279) compared to CON. No treatment by day interaction (P > 0.05) was observed for WBSF, objective color, subjective color score, or discoloration during the retail display period. However, WBSF decreased (P < 0.0001) over the aging period. Further, L* values increased (P < 0.001) from day 0 to day 10, while a* values and b* values decreased (P < 0.0001) during the display period. Similarly, subjective color scores increased (P < 0.0001) indicating samples appeared darker as display dates increased. Lipid oxidation also increased (P < 0.0001) over the display period. These data indicate that the inclusion of an oregano-based essential oil has limited impact on the growth performance, carcass traits and meat quality of steers.

Publisher

South Dakota State University

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Included in

Beef Science Commons

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Rights Statement

In Copyright