Date of Graduation

8-2024

Document Type

Thesis

Degree Name

Master of Science in Animal Science (MS)

Degree Level

Graduate

Department

Animal Science

Advisor/Mentor

Rivera, Daniel

Committee Member

Coffey, Kenneth P.

Second Committee Member

Gadberry, Shane

Keywords

Finishing methods; Diet; Cattle; Beef

Abstract

The objective of these studies was to evaluate the effects of alternative finishing methods on the live performance, carcass quality, and meat characteristics of beef steers. In study 1, treatments consisted of a conventional feedlot finishing diet with roughage included in the ration (FDLT); a high starch diet fed at 2-2.25% of BW with ad libitum access to bermudagrass pastures (STCH); or a high by-product diet fed at 2-2.25% of BW with ad libitum access to bermudagrass pastures (BYPD). Steers were fed their respective diets once daily and weighed every 28 days until deemed finished. Cattle were then transported and harvested at a commercial slaughter facility where carcass data were collected. Cattle fed FDLT and BYPD had a greater BW on d 112 and 140 (P ≤ 0.02) and greater overall carcass-adjusted BW (P = 0.03) compared to STCH. Average daily gain was greater between d 57-84 (P = 0.03) for FDLT. Overall carcass-adjusted ADG tended (P = 0.09) to be greater for FDLT and BYPD. As expected, cattle fed FDLT had greater DMI than STCH and BYPD for the entire study (P ≤ 0.0005). Both STCH and BYPD had a more efficient feed-only feed conversion through d 56, between d 85-140, and when averaged across d 0-161 (P ≤ 0.05). Hot carcass weight tended (P = 0.13) to be greater for BYPD and FDLT. Marbling score tended (P = 0.14) to be greater for BYPD. No differences (P ≥ 0.34) were noted for DP, BF, PYG, YG, REA, or QG. In study 2, strip loins were collected from the left side of each carcass, vacuum packaged, wet aged for 21 d at 0-4°C, and then fabricated into 2.54 cm thick steaks designated for instrumental color, WBSF, and trained sensory analysis. A diet × day interaction (P ≤ 0.0006) occurred for a*, chroma, and hue. Beginning on d 4 of display, steaks from cattle fed FDLT were less red with a lower saturation index compared to steaks from cattle fed STCH and BYPD. Steaks from FDLT had a greater (P < 0.0001) hue angle on d 6 and 7. There were no diet × day interactions (P ≥ 0.36) for L* and b* values. Diet resulted in greater (P < 0.0001) L* values for BYPD and FDLT. However, diet resulted in greater (P < 0.0001) b* values for BYPD and STCH. A significant effect of day (P < 0.0001) resulted in L* and b* values decreasing over 7 d. Steaks from cattle fed BYPD had lower (P = 0.02) WBSF values. Cook loss was greater (P = 0.01) for FDLT. For trained sensory analysis, connective tissue amount was greater (P = 0.02) for STCH. Myofibrillar tenderness and overall tenderness tended (P ≤ 0.10) to be greater for BYPD. No differences (P ≥ 0.65) were noted for beef flavor intensity, off-flavor intensity, initial juiciness, or sustained juiciness. Data from these studies suggest alternative finishing methods utilizing beef cattle grazing pasture could successfully be used without affecting product quality.

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