Document Type

Thesis - University Access Only

Award Date

2004

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Duane Wulf

Abstract

Two hundred forty Angus crossbred steers were used to determine the influence of feeding various levels of wet and dry distiller's grains to finishing steers on carcass characteristics, meat quality, retail case life of ground beef, and fatty acid profile of longissirnus muscle. Three replications of five dietary treatments were randomly applied to the 15 pens for each of two years. A finishing diet containing com, soybean meal and alfalfa hay was fed as the control diet. Wet distiller's grains with solubles (WDGS) or dry distiller's grains with solubles (DDGS) were added to the finishing diets at either 20.0 or 40.0% of the diet dry matter to replace all soybean meal and part of the cracked com in treatment diets. Carcasses of steers fed distiller's grains with solubles (DGS) had greater (P < 0.05) fat thickness (1.47 vs. 1.28 cm), higher (P < 0.05) USDA yield grades (3.23 vs. 2.94), and a lower (P < 0.05) percentage of yield grades 1 and 2 (41.1 % vs. 60.4%) than carcasses of steers fed the control diet. Carcasses from steers fed 20% DGS had higher (P < 0.05) marbling scores (Sma11 50 vs. Small24 ) than carcasses from steers fed 40% DGS. Longissimus muscle from steers fed DOGS had higher (P < 0.05) ultimate pH values (5.52 vs. 5.49) than longissimus muscle from steers fed WDGS. Ground beef from steers fed DGS had higher (P < 0.05) levels of a-tocopherol (1. 77 vs. 1.43 μgig) than ground beef from steers fed the control diet. Ground beef from steers fed 40% DOS had higher (P < 0.05) TEARS (2.84 vs. 2.13 mg/kg) on d 2 of retail display than ground beef from steers fed 20% DGS. Longissimus muscle of steers fed DGS had lower (P < 0.05) levels of Cl 7:0 and C18: lc9 and higher levels of C18:0, C18: lt, C16:lc9, C18:2c9c12, and total polyunsaturated fatty acids (PUFA) than longissimus muscle of steers fed the control diet. Feedlot steers fed distiller's grains may need to be marketed earlier than normal to avoid excess external fat and yield grade 4' s. Dietary levels of 40% distiller's grains in finishing cattle diets may reduce marbling compared to 20% levels. Feeding DGS to finishing steers will probably have no adverse or beneficial effects on glycolytic variables (dark cutters), ground beef retail display life, or meat tenderness. Beef from cattle finished on diets containing DGS will probably have a higher proportion of PUF A and therefore be more susceptible to oxidative rancidity.

Library of Congress Subject Headings

Beef cattle -- Feeding and feeds
Distillers feeds
Beef cattle -- Carcasses
Beef -- Quality

Publisher

South Dakota State University

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Rights Statement

In Copyright