Purified corn and wheat starch were added to alfalfa, Coastal bermudagrass, fescue, and orchardgrass hays at 0, 40, 60, and 80% of the total as-fed substrate, and fiber digestion kinetics were determined in vitro. Kinetics were estimated by the model R = DOe−k(t−L) + U where R is residue remaining at time t, DO is digestible fraction, k is digestion rate constant, L is discrete lag time, and U is indigestible fraction. Parameters of the model were estimated by logarithmic transformation and a direct nonlinear least squares procedure. Corn and wheat starch did not differ in their effect upon lag time of fiber digestion, digestion rate, or potential extent of digestion. Alfalfa had a shorter lag time of fiber digestion (.86 h) than Coastal bermudagrass (3.05 h), but not than orchardgrass or fescue (1.66 and 2.42 h). Orchardgrass differed in fiber digestion rate (.0542h−1) from Coastal bermudagrass (.0698h−1) but not from alfalfa or fescue (.0670 and .0658h−1). The potential extent of fiber digestion was similar for fescue (75.8%) and orchardgrass (76.0%). The potential extent of fiber digestion for alfalfa (50.9%) differed from Coastal bermudagrass (64.3%), and both of these forages differed from fescue or orchardgrass. Addition of starch resulted in a linear increase in lag time of fiber digestion, but digestion rate was not affected. Potential extent of digestion was decreased when starch was added. © 1980, American Dairy Science Association. All rights reserved.
CITATION STYLE
Mertens, D. R., & Loften, J. R. (1980). The Effect of Starch on Forage Fiber Digestion Kinetics In Vitro. Journal of Dairy Science, 63(9), 1437–1446. https://doi.org/10.3168/jds.S0022-0302(80)83101-8
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