Browsing by Author "Smith, Jason K"

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    Implications of Site and Extent of Protein Digestion in Growing and Finishing Cattle
    (2023-10-26) Proctor, Jarret Allen; Smith, Jason K; Beck, Matthew R; Bell, Jourdan M; GouvĂȘa, VinĂ­cius N; Wickersham, Tryon A.
    Voids in our current knowledge of protein nutrition for growing and finishing cattle include adequate characterization of the site and extent of protein digestion and the environmental and economic consequences of a disparity between protein supply and dietary requirements. A series of studies were conducted to create a robust dataset to predict the site and extent of protein digestion for ingredients commonly fed to cattle and to evaluate the impact of altering dietary rumen degradable protein intake on finishing cattle performance and gas flux. Prediction models were developed for rumen degradable protein and intestinal digestion of rumen undegradable protein using ingredient nutrient composition as predictors with high coefficients of determination. Developed equations explained a substantial portion of variation and had excellent agreement when evaluated against an independent dataset compiled from peer-reviewed literature. Regardless of rumen degradable protein intake level, cattle emitted similar amounts of carbon dioxide equivalents. However, cattle consuming intermediate levels of rumen degradable protein had an advantage in total mixed ration intake and marbling score and optimized nitrogen excretion and emission footprint. Data obtained while evaluating gas flux facilitated a calculation of dietary energy values using a gas-adjustment method, which was highly correlated and had excellent agreement with performance-adjusted dietary energy values. This research provides improvement in our understanding of the site and extent of protein digestion. This information can be utilized in strategic ration formulation when estimating metabolizable protein supply and the impact of dietary rumen degradable protein concentration on finishing cattle performance and gas emissions.