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

优质的饲料是实现奶牛高产能和高营养效率的基础。好氧诱导青贮再加热是造成奶牛场能量和营养损失的主要原因之一。在最坏的情况下，进料可能完全变质。青贮料在贮藏阶段塑料覆盖物破损或饲喂前暴露在空气中，青贮料好氧再加热的风险较大。青贮温度的变化是由微生物代谢引起的，受多种因素（如基质、容重和含水量）的影响。为了预测青贮温度的分布和动态，提出了基于偏微分方程（PDE）的二维空间热、氧、湿耦合输运分析模型。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质量和能量损失以及预测青贮变质风险。提交的提案将通过一个长期成立的中德研究小组，针对草和苜蓿青贮材料的这些目标。对圆捆青贮进行了三个方面的初步研究：(1)在二维和三维地图上的容重和水分分布；（ii）被刺穿一个或两个洞时的二维温度变化及分布情况；（iii）在一个或两个点被刺破的情况下基于模型的模拟。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。实验研究将开始于草和苜蓿密封在瓶/桶中（第一年），草打包成包（第二年），苜蓿打包成包（第三年）。预期成果包括：发表具有影响因子的高水平论文、基于模型的软件和案例应用、双方在饲料研究领域的青年科学家推广和专利。关键词：温度，青贮，覆盖物损坏，好氧变质，再加热模型，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.