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

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Bonesmo, H. Articles by Bélanger, G. Search for Related Content PubMed Articles by Bonesmo, H. Articles by Bélanger, G. Agricola Articles by Bonesmo, H. Articles by Bélanger, G. Related Collections Agroclimatology Crop Growth and Development Other Forage Crops Crop Models

MODELING

Timothy Yield and Nutritive Value by the CATIMO Model

II. Digestibility and Fiber

^a Norwegian Crop Res. Inst., Kvithamar Res. Cent., NO-7500 Stjordal, Norway
^b Soils and Crops Res. and Dev. Cent., Agric. and Agri-Food Can., 2560 Hochelaga Blvd., Sainte-Foy, QC, Canada G1V 2J3

* Corresponding author (belangergf{at}em.agr.ca)

Received for publication December 4, 2000. Growth and nutritive value of forage crops have rarely been integrated into one mechanistic computer simulation model. In a companion paper, we described the growth and N concentration modules of an integrated model of timothy (Phleum pratense L.) primary growth and nutritive value, known as CATIMO (Canadian Timothy Model). In this paper, we describe the digestibility module, which features the cell wall (CW) digestibility and CW concentration for each of the plant morphological components derived from the growth module of the model. The model parameters were calibrated to key model attributes: concentration and digestibility of CW in leaves, stems, and forage and dry matter (DM) digestibility of leaves, stems, and forage. Calibration measurements were taken weekly on timothy primary growth in four different years at one location (Fredericton, NB, Canada). The model satisfactorily fitted the measured values with root mean square errors of estimation (RMSE) of 0.051 g g^-1 DM for forage CW concentration, 0.026 g g^-1 CW for forage CW digestibility, and 0.018 g g^-1 DM for forage DM digestibility. The leaf and stem CW concentration (RMSE 0.044 g g^-1 DM), CW digestibility (RMSE 0.019 g g^-1 CW), and DM digestibility (RMSE 0.018 g g^-1 DM) were also calculated satisfactorily by the model. The CATIMO model is a promising tool because of its mechanistic and flexible approach and the good agreement between measured and simulated values.

Abbreviations: CW, cell wall • DM, dry matter • IVTD, in vitro true dry matter digestibility • RMSE, root mean square error of estimation

This article has been cited by other articles:

				H. Bonesmo, G. Belanger, E. Charmley, R. Drapeau, D. B. McKenzie, R. Michaud, and G. F. Tremblay Timothy Yield and Nutritive Value by the CATIMO Model: III. Validation for Eastern Canada Agron. J., January 1, 2005; 97(1): 32 - 40. [Abstract] [Full Text] [PDF]

				H. Bonesmo and G. Belanger Timothy Yield and Nutritive Value by the CATIMO Model: I. Growth and Nitrogen Agron. J., March 1, 2002; 94(2): 337 - 345. [Abstract] [Full Text] [PDF]