Model-based research for the risk prediction of silage bale deterioration suffered from aerobic stress

优质的饲喂材料是实现奶牛高产高效、营养高效的基础。青贮料充氧复温是造成奶牛养殖场能量和营养损失的主要原因之一。在最坏的情况下，进料材料可能会完全变质。当青贮料的塑料覆盖物在储藏阶段被损坏或青贮料在饲喂前暴露在空气中时，青贮料因好氧引起的重新加热的风险可能相当高。微生物代谢引起的青贮料温度变化受多种因素(如基质、堆积密度、水分等)的影响。为了预测青贮料中的温度分布和动态变化，采用偏微分方程组(PDE)建立了青贮料在二维空间中的热、氧、湿耦合传输的解析模型。影响温度的化学反应和微生物反应已在相关文献中概述。然而，有限的研究集中在验证这些模型，以估计青贮料质量和能量损失，并预测青贮料变质的风险。提出的建议将通过一个长期成立的中德研究小组，旨在实现草和紫花苜蓿青贮料的这些目标。对圆包青贮料进行了三个方面的初步研究：(1)二维和三维图上的堆积密度和水分分布；(二)单孔和双孔情况下二维地图上的温度过程和分布；(三)单点和两点穿孔情况下的基于模型的模拟。对于进一步提出的研究，将处理具有三个关键参数(温度、氧气浓度和水分含量)的PDE系统。实验研究将从青草和紫花苜蓿装瓶/桶(第一年)开始，草包装成包(第二年)，紫花苜蓿包起来(第三年)。预期成果包括影响因子的高水平出版物、基于模型的软件和案例应用、双方在饲草研究领域的青年科学家推广和专利。关键词：温度、包青贮料、盖层损坏、好氧变质、再热模型、风险预测。

High quality of feeding materials is the basis of achieving high productivity of milking cows and high nutrition efficiency. Silage reheating aerobic-induced is one of the main causes for energy and nutrition losses on dairy farms. In the worst case, the feeding material can be totally deteriorated. The risk of silage reheating aerobic-induced could be quite high when the plastic cover of silage is damaged during the storage phase or when silage exposes itself to air before feeding. The temperature Variation of silage due to the metabolism of microorganism is influenced by various factors (e. g. the substrate, the bulk density and the water content). To predict the silage temperature distribution and dynamics in silage, some analytical models of coupled heat, oxygen and moisture transport with partial differential equations (PDE) in 2D space have been presented. The chemical and microbial reactions that influence the temperature have been outlined in the relevant literatures. However, limited studies focus on validating these models for estimating the silage mass and energy losses and for predicting risk of silage deterioration. The presented proposal will aim at these goals for grass and alfalfa silage materials through a long-term established Sino-German research group. Preliminary study has been conducted with round bale silage on three aspects: (i) bulk density and moisture distribution in 2D and 3D map; (ii) temperature progress and distribution in 2D map in the case of being punctured with one or two holes; (iii) model-based simulation in the case of being punctured with one or two points. For the study proposed in further, a PDE system with three key parameters (temperature, oxygen concentration and moisture content) will be treated. The experimental study will start with grass and alfalfa sealed in bottle/ bucket (first year), grass packed as around bale (second year), alfalfa packed as bale (third year). The expected achievements include high-level publications with impact factors, model-based software and case application, young scientist promotion in forage research area for both sides and patent.Keywords: temperature, bale silage, cover damage, aerobic deterioration, reheating models, risk prediction.