Evaluation de différents modèles mathématiques appliqués à la méthode in sacco dans la caractérisation de la valeur nutritive de graminées tropicales et secondaires tempérées pour l’alimentation des ruminants
(2012)
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- (en) The objectives of this study were: 1) to choose a mathematical model that is better suited to fit to the in sacco degradation data of three secondary temperate grass hays of the Wallonian part of Belgium and three tropical fresh grasses of Burundi, 2) to estimate the nutritive value of these grasses from (among others) the degradation parameters of the selected model, and 3) to assess the ability of these parameters to predict forage organic matter digestibility (OMD) as compared to other laboratory methods. In this perspective, we conducted degradability / digestibility trials and compared different mathematical models and forage evaluation methods. The results showed that the Gompertz lagged model was the best suited to fit to the degradation data of both temperate and tropical grasses and that the search for a fitting model should be limited to the sigmoid type functions due to their greater flexibility. Under our experimental conditions, relatively interesting energy and protein values were recorded for the studied secondary grasses. These grasses had interesting dry matter yields and confirmed their interest in extensive or semi-extensive production systems that require low inputs and preserve environment. Our results showed that the tropical studied grasses were used at a late stage of maturity and their intake was not able to meet the maintenance requirements of the experimental animals. They also revealed that the half-life period t1/2 of the slowly degradable fraction S0 was the best single degradation parameter to predict forage OMD and that the degradation rate μ1/2 at time t1/2 and the constants b and c of the model were able to improve significantly the prediction precision of equations including fractions W and / or S0.
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Nivyobizi, A. (2012). Evaluation de différents modèles mathématiques appliqués à la méthode in sacco dans la caractérisation de la valeur nutritive de graminées tropicales et secondaires tempérées pour l’alimentation des ruminants. https://hdl.handle.net/2078.5/160662