TY - JOUR
T1 - Simplified estimation of forage degradability in the rumen assuming zero-order degradation kinetics
AU - Lopez, S.
AU - Sanderson, Ruth
AU - France, Jim
AU - Dhanoa, M. S.
N1 - Dhanoa, M. S., Lopez, S., Sanderson, R., France, J. (2009). Simplified estimation of forage degradability in the rumen assuming zero-order degradation kinetics. Journal of Agricultural Science, 147, (3), 225-240.
Sponsorship: Canada Research Chairs Programme
IMPF: 01.66 RONO: 3130
PY - 2009/6/1
Y1 - 2009/6/1
N2 - In the present paper, a simplified procedure using few in situ data points is derived and then evaluated (using a large database) against reference values estimated with the standard nylon bag first-order kinetics model. The procedure proposed involved a two-stage mathematical process, with a statistical prediction of some degradation parameters (such as lag time) and then a kinetic model derived by assuming degradation follows zero-order kinetics to determine effective degradability in the rumen (E). In addition to the estimation of washout fraction and discrete lag, which is common to both procedures, the simplified procedure requires measurement of dry matter losses at one incubation time point only. Thus, interference of the animal rumen will be much reduced, which will lead to increased capacity for feed evaluation. Calibration of the zero-order model against the first-order model showed that suitable estimates of E can be obtained with disappearance at 24, 48 or 72 h as the single incubation end time point. The strength of the calibration is such that an end incubation time point as low as 24 h may be sufficient, which may reduce substantially the total incubation time required and thus the impact on the experimental animal. Relevant regression equations to predict reference values of parameters such as lag time or E are also developed and validated.
AB - In the present paper, a simplified procedure using few in situ data points is derived and then evaluated (using a large database) against reference values estimated with the standard nylon bag first-order kinetics model. The procedure proposed involved a two-stage mathematical process, with a statistical prediction of some degradation parameters (such as lag time) and then a kinetic model derived by assuming degradation follows zero-order kinetics to determine effective degradability in the rumen (E). In addition to the estimation of washout fraction and discrete lag, which is common to both procedures, the simplified procedure requires measurement of dry matter losses at one incubation time point only. Thus, interference of the animal rumen will be much reduced, which will lead to increased capacity for feed evaluation. Calibration of the zero-order model against the first-order model showed that suitable estimates of E can be obtained with disappearance at 24, 48 or 72 h as the single incubation end time point. The strength of the calibration is such that an end incubation time point as low as 24 h may be sufficient, which may reduce substantially the total incubation time required and thus the impact on the experimental animal. Relevant regression equations to predict reference values of parameters such as lag time or E are also developed and validated.
U2 - 10.1017/S0021859608008241
DO - 10.1017/S0021859608008241
M3 - Article
SN - 0021-8596
VL - 147
SP - 225
EP - 240
JO - Journal of Agricultural Science
JF - Journal of Agricultural Science
IS - 3
ER -