No description available.

The present series of experiments were carried out to determine the effect of i) ensiling straw and grass in various proportions, on chemical composition and nutritive value of silage, ii) homogeneity of mixing of grass and straw on fermentation quality and nutritive value of silage, iii) urea and/or enzyme treatment of straw on chemical composition and nutritive value of grass+ straw silage, and iv) co-conservation of grass-straw on nutritive value of straw. In some experiments feeding value is assessed in the laboratory, and in others by actual feeding trial. In addition a method was developed for determining water in silages using near infrared transmittance spectroscopy. Mixing straw with grass during ensiling diluted crude protein but increased the cell wall constituents. Straw modified fermentation, and more lactic acid and acetic acid were produced in grass+ straw silage than grass-only silage. The fermentation was also affected by the type of grass. The concentrations of ammonia were higher and lactic acid and acetic acid were lower in the silages made from grass/legume than that from only grass. A thorough mixing of grass+ straw is required because ensiling grass and straw in alternate layers increased butyric acid content in silage. Animals ate 22% less dry matter from the silage made in layers than from that made from thoroughly mixed grass+ straw. However, more intensive mixing of grass and silage was not beneficial, as it reduced the digestibility of nutrients and only slightly increased dry matter intake. Increasing the proportion of straw in grass+ straw in a grass+ straw silage reduced intakes of dry matter and digestibility of nutrients. Treatment of straw with urea (60 g/kg straw DM) increased lactic acid content and reduced the contents of cell wall constituents. Urea increased intake and digestibility of nutrients, but enzyme had small effect on intake and digestibility of nutrients by sheep. However, a combination of urea and enzyme was most effective, and increases in the intake of dry matter and digestibility of nutrients were significantly greater in these silages than those treated with either urea or enzyme. The straw composition of cell wall constitutents from straw occurred during ensiling. A method developed for determination of water using NITS is fast and reliable. The model uses the absorbance ratio (OD at 1940 nm/OD at 2284 nm) as a predictor of water in dimethyl sulphoxide which was used to extract water from silages.

Novel approaches to manipulating proteolysis in ensiled perennial ryegrass (PRG) were investigated. The effects of the following on nitrogen (N) distribution in silage were investigated: E- 64, a specific cysteine-peptidase inhibitor (CPI); pepstatin A a specific aspartic-peptidase inhibitor; cystamine dihyrochloride (CYS) and N-ethylmaleimide, general CPIs, and formic acid (FA). Treatment with FA or CPIs reduced total soluble N, as a result of reduced proteolysis, and FA and CYS treatments increased peptide N concentrations (determined using fluroescamine or ninhydrin assays, and by amino acid analysis) compared to the control. Pepstatin A had little or no effect on the N constituents of silage. Characterisation of silage peptides using Sephadex G-25 suggested that they were predominantly di and tripeptides, with a small proportion of longer peptides (>7 amino acid residues). Forty additional compounds were screened for their efficacy as inhibitors of proteolysis in aqueous extracts of PRG. Five selected compounds were applied to PRG at ensilage: TPCK, a non specific CPI; chelators, 1,10-phenanthroline and 8-hydroxyquinoline (8-HQ); bestatin, a metallo-peptidase inhibitor; and N-acetyl-L-tyrosine ethyl ester (ATEE), a serine-peptidase inhibitor. When compared to the control, TPCK and 1,10- phenanthroline reduced total soluble N and increased peptide N concentrations; 8-HQ increased only peptide N concentrations. These chelators also restricted fermentation. The effects of Trypticase (peptides produced by enzymic hydrolysis of casein), silage extracts and N fractions prepared from silage extracts by cation exchange chromatography, as sources of N, on the growth of rumen bacteria, <I>Megasphaera elsdenii, Prevotella ruminicola</I> and <I>Selenomonas ruminantium, </I>supplied with glucose as an energy substrate <I>in vitro, </I>were investigated. No growth was observed on media containing extracts from silages produced in the presence of chelators but all bacteria grew on purified N fractions. Increasing silage peptide N therefore did not enhance microbial growth but for some treatments, silage N supported faster growth than Trypticase.

Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisor: Limin Kung, Jr., Dept. of Animal and Food Sciences. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 58-69). Also available via the Internet.

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 71-77.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / Typescript. Appendix: "The influence of fertilizer nitrogen, phosphorus, and potassium on some indicators of nutritive value of corn and resultant silage, 1965 study [by] R.H. Stauffacher [and others]*: p. 71-82. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 25-26.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.