J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bach, A.
Right arrow Articles by Drackley, J. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bach, A.
Right arrow Articles by Drackley, J. K.

Journal of Animal Science, Vol 76, Issue 11 2885-2893, Copyright © 1998 by American Society of Animal Science

JOURNAL ARTICLE

Evaluation of selected mathematical approaches to the kinetics of protein degradation in situ

A. Bach, M. D. Stern, N. R. Merchen and J. K. Drackley
Department of Animal Science, University of Minnesota, St. Paul 55108, USA.

A linear model, two mathematical nonlinear models, and a curve-peeling procedure were used to estimate rate and extent of ruminal CP degradation of meat and bone meal (MBM) and soybean meal (SBM) from data obtained using the in situ Dacron polyester bag technique. Most of the values for extent of CP degradation of MBM were lowest when determined using curve peeling or the nonlinear models. In general, rates and extents of CP degradation of MBM estimated using the linear model and including ruminal incubations up to 12 h were greater than those obtained with the linear model and including ruminal incubations up to 24 h or up to 72 h. In addition, the models ranked the MBM samples differently for rate and extent of CP degradation. The results of the lack-of-fit test indicated that the linear model was inappropriate for estimating rate of degradation of MBM. However, CP degradation for SBM could be described by the linear model if long ruminal incubation times (greater than 48 h) were included in the calculations. Regression analyses were conducted to evaluate various compositional characteristics as predictors of CP degradation for MBM. Most of the correlation coefficients between CP degradation and the same independent variables were greater when the nonlinear models and curve peeling were used compared with the linear model. In general, the correlation coefficients between extent of CP degradation and the independent variables obtained with the linear model increased as the duration of ruminal incubations included in the model increased. Lysine concentrations, followed by CP solubility and ash content, were the best predictors of ruminal degradation of MBM protein. When using a specific mathematical model to predict CP degradation, analysis of residuals vs fitted and lack-of-fit tests should be performed to assess the validity of the model to describe the degradation patterns of the protein source under consideration. Also, long (at least 48 h) ruminal incubation times may be needed to correctly describe the pattern of CP degradation for MBM.


This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
J. L. Firkins, A. N. Hristov, M. B. Hall, G. A. Varga, and N. R. St-Pierre
Integration of Ruminal Metabolism in Dairy Cattle
J Dairy Sci, March 1, 2006; 89(e_suppl_1): E31 - E51.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1998 by the American Society of Animal Science.