http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
fragmentation and flow of forage residues through the gastrointestinal tract of cattle
The structural fragmentation of Coastal bermudagrass (Cynodon dactylon) and ryegrass (Lolium multiflorium) resulting from ingestive mastication and remastication subsequent to rumination was observed microscopically and histochemically. Sites of fragmentation and origin of plant tissue which comprised the various sized fragments ingested and present in the rumen were determined. The fragmentation of plant tissues appears primarily the result of mastication. Several one and two compartment models with and without age dependency were derived and fitted to marker excretion data after a single marker dose. The mathematical derivation, experimental application and computations of flow, fill and digesta output were discussed. Age dependent models fitted the data with lower model residual sum of squares and fitted data that previously were not successfully fitted to age independent models. A method was developed to simultaneously measure the concentration of ten elements suitable as nutritional markers. These markers were then used to label different fiber sources dosed to the same animals in order to obtain passage parameter estimates for each fiber source. The fiber was soaked in the marker solutions overnight followed by thorough rinsing. This soak and rinse procedure reduces the incidence of nonuniform labeling or exceeding the binding capacity of the fiber. These have been typical problems associated with labeling accomplished by spraying or sprinkling. Similar passage parameter estimates were obtained for rare earth elements as compared to Cr-mordanted fiber. This indicates that the rare earth elements may be used as particulate flow markers. Differences in passage parameter estimates were observed when dosing occurred at the beginning as compared to the end of a meal. These observations were discussed in relation to the reticulo-ruminal motility and movement of digesta. When dosing of different markers occurred at the beginning of meals at 24 h intervals, parameter estimates were similar. A two marker-two dose technique was described in which fewer number of samples would be required to measure flow, fill and digesta output.
Ph. D. in Philosophy Texas A & M University 1982
Includes bibliographical references (leaves 134-140).