Woody plant encroachment (WPE) poses the greatest threat to the sustainability of Great Plains rangelands and the agricultural commodities produced there. With the loss of grasslands and the economic impact of WPE, it is especially important to understand the effects of modern brush management strategies and their implications for livestock production in the Great Plains. My experiments aim to improve grazing systems by understanding the mechanics of multispecies grazing and pyric herbivory on diet selection and intake of cattle and goats grazing woody plant encroached pastures. Furthermore, my experiments attempt to deepen the understanding of the digestion of targeted invasive species consumed by goats. My results indicate that cattle and goats select a diverse diet in encroached pastures, and selection is dynamic over time and in the presence of prescribed fire. The presence of goats in a pasture does not significantly alter the diet selection of cattle. Instead, goats are complementary to cattle by targeting plant species that cattle do not prefer. From my results, no evidence was found to suggest that woody plant proliferation influences gross mass of dry matter intake or as a percentage of body weight in cattle or goats. Additionally, my results parameterize rumen kinetics and metabolism of the highly invasive legume, Sericea lespedeza (Lespedeza cuneata). My results demonstrate that sericea is a less degradable legume than alfalfa. While sericea lespedeza created a more favorable rumen pH, sericea consumption resulted in increased acetate proportions and acetate:propionate ratios. Reduction of protein degradability was demonstrated through decreased ruminal NH3–N and branched chain VFA proportions. Furthermore, degradability of a grain supplement was negatively affected by feeding a sericea lespedeza diet.