HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Denham, S. C. Articles by Moore, J. E. Search for Related Content PubMed Articles by Denham, S. C. Articles by Moore, J. E.

Comparison of Two Models Used to Estimate In Situ Nitrogen Disappearance¹

Animal Science Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville 32611

ABSTRACT

Inclusion of lag time into a model describing in situ N disappearance influenced the parameter estimates describing N degradability and improved the goodness-of-fit of the model to data describing aeschynomene hay and alfalfa meal digestion. Ruminal N disappearance (%) was described using two models that assumed: 1) digestion of the potentially digestible but insoluble N fraction was initiated immediately upon exposure to ruminal contents, or 2) digestion of this fraction was preceded by a lag period during which hydration and microbial attachment is presumed to occur prior to the initiation of digestion. Digestion was assumed to occur from a homogeneous potentially digestible but insoluble N fraction by a first order process described by a rate constant, k. Incorporating a lag term resulted in an increase in the rapidly soluble N fraction, a decrease in the potentially digestible but insoluble N fraction, and a decrease in the total digestible N fraction. The two forages had different k values when fit to the nonlagged model but not when fit to the lagged model. The residual standard deviation was smaller for the lagged model, and the fit of predicted values to observed values was improved.

¹ Florida Agricultural Experiment Station Journal Series No. 9139.

² To whom requests for reprints should be addressed.

³ Present address: Purina de Venezuela, Ave. Principal de los Ruices, Edif. Stemo, 4to Piso, Caracas, Venezuela.

This article has been cited by other articles:

				S. I. Borucki Castro, L. E. Phillip, H. Lapierre, P. W. Jardon, and R. Berthiaume Ruminal Degradability and Intestinal Digestibility of Protein and Amino Acids in Treated Soybean Meal Products J Dairy Sci, February 1, 2007; 90(2): 810 - 822. [Abstract] [Full Text] [PDF]