Document Type
Dissertation - University Access Only
Award Date
1990
Degree Name
Doctor of Philosophy (PhD)
Department / School
Animal Science
Abstract
In vitro studies were conducted to determine the effects of amino acid or branchedchain volatile fatty acid buffer additions on rate and extent of digestion of dormant range grasses. Two digestion trials were conducted to evaluate controlled release chromic oxide (Cr) intraruminal boluses and alkaline hydrogen peroxide lignin (APL) as potential markers for indirect determination of forage intake by the fecal output (FO)/indigestibility ratio. A digestibility trial and a 2-year grazing study utilizing 103 mature crossbred cows were conducted to determine the effect of methionine addition to a urea-grain supplement on intake and digestibility of dormant range grasses and cow performance. The primary nitrogen source contained in each supplement was urea, urea plus DL-methionine (MET), urea plus sodium sulfate (SUL) or soybean meal (SBM). In vitro screening of amino acid or branched-chain volatile fatty acid buffer additions to dormant range grasses showed that methionine supplementation with urea offers the greatest potential, among the supplements evaluated, for improving digestibility and rate of fermentation of cool season grasses. None of the buffer supplements improved fermentation of the warm season grasses. Validation of marker procedures indicate that grab samples collected once daily on 5 consecutive days can be used to predict fecal output when controlled release Cr boluses are used. While accuracy of dry matter digestibility estimates based on APL were more variable, the marker validation trial indicated that accurate predictions of dry matter intake can be made. Methionine addition to a urea-grain supplement for cows grazing dormant winter range did not increase intake or digestibility of dormant range grass or improve performance of cows grazing dormant winter range. It appears that methionine addition to a urea-grain based supplement decreased forage digestibility late in the winter grazing period resulting in depressed animal performance.
Library of Congress Subject Headings
Beef cattle -- Feeding and feeds Beef cattle -- Wintering Urea as feed Methionine Feed additives
Format
application/pdf
Number of Pages
83
Publisher
South Dakota State University
Recommended Citation
Momont, Patrick A., "Effect of Methionine Addition to a Urea-grain Supplement on Intake and Digestibility of Mature Dormant Grasses and Performance of Cows Grazing Winter Range" (1990). Electronic Theses and Dissertations. 1166.
https://openprairie.sdstate.edu/etd2/1166