Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Animal Science

Major Professor

John C. Waller

Committee Members

B.R. Bell, D.L. McLemore


A methodology for the evaluation of byproducts as a potential feedstuffs for ruminant diets was developed. The development process involved 1) development of methodology for the preliminary evaluation of a byproduct as a potential livestock feed. The methodology was tested using wet corn gluten feed (WCGF) as a model byproduct; 2) the construction of a least-cost linear program model to evaluate the value of a feedstuff on the basis of nutritional properties exhibited; 3) the application of the byproduct (WCGF) to specific feeding systems

The methodology for preliminary evaluation of a byproduct indicate that WCGF appears to be free of any physical or chemical characteristics which would hinder or inhibit the use of WCGF as a feedstuff for growing and finishing beef cattle diets. The protocol did not address all issues necessary for dealing with wet materials. Additional suggestions were made to increase the thoroughness of the methodology for evaluating wet materials.

Least-cost linear program models, the crude protein (CP) and rumen degradable protein (RDF) models, were evaluated as to their effectiveness in describing the economic value of nutrient constituents within a feedstuff. The RDF model was determined superior over the CF model in describing the economic value of feedstuff considered for inclusion in growing steer diets. The RDP model gave economic advantage to feeds containing unique protein qualities which are required by growing (215 kg) steers for maximum growth and development. The RDP and CP models were found to formulate identical rations for finishing (318 kg) steers. The CP system is recommended for evaluating diets of heavy weight class of steers due to the greater availability of CP values over RDP values.

Application of the RDP model to WCGF determined WCGF to be of negative economic value in growing steer diets. WCGF demonstrated value as an energy source for finishing steer diets, when included up to 15% of ration dry matter. The high variability of the nutrient content of WCGF resulted in a considerable discount in the nutrient value credited to WCGF, and may have caused a reduction in the dietary levels of WCGF included in finishing diets.

This study provides a combination of methodology and technical procedures by which a byproduct can be thoroughly evaluated for factors effecting the manageability, nutrient quality, economic value and safe application of the material considered for inclusion in beef cattle diets.

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