High-yielding dairy cows collapsed and died displaying signs of a disturbed central nervous system (muscle tremor, convulsion) and a considerably reduced body condition score. An intense diagnostic screening did not allow to confirm a definite diagnosis. Therefore, further analyses including an evaluation of feeds and feeding were initiated. The herd was fed a total mixed ration (TMR) based on corn and grass silage of moderate nutritive value supplemented with various amounts of chocolate chips. In retrospect, the amount of chocolate chips added to the respective TMR batches could not be quantified. These chips were purchased from a company producing bakery and chocolate products for human consumption and added to the silage and therefore to the TMR in order to increase the energy intake of the animals. Because the TMR, which was fed during the time of the incidence, was no longer available, a sample of a later batch of silage was examined. The amount of chocolate chips was quantified (0.44% per fresh matter), and a theobromine analysis was performed in the chocolate chips of the available batch (69.7 mg/100 g fresh matter). Because of the possible link between chocolate intake and observed signs, an immediate cessation of using the chocolate chips was recommended in addition to an optimisation of the TMR, that is an increase of the energy density. Even though the theobromine intake during the time of the incidence is unknown and information about toxicity of theobromine in ruminants is limited, we suspect that the feeding of chocolate in this case caused all signs including the sudden death of the cows. Further reasons are that no differential diagnoses were established and the problems at the farm stopped after removing the chocolate from the TMR.

中文翻译：

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奶牛疑似可可碱中毒案

高产奶牛倒下并死亡，表现出中枢神经系统紊乱（肌肉震颤、抽搐）和身体状况评分显着降低的迹象。密集的诊断筛查无法确认确诊。因此，开始了进一步的分析，包括对饲料的评估和饲养。牛群饲喂以中等营养价值的玉米和青草为基础的全混合日粮 (TMR)，并辅以不同数量的巧克力片。回想起来，添加到各个 TMR 批次中的巧克力片数量无法量化。这些薯片是从一家生产供人类食用的烘焙和巧克力产品的公司购买的，并添加到青贮饲料中，因此添加到 TMR 中以增加动物的能量摄入。因为TMR，在发病期间饲喂的青贮饲料不再可用，检查了后来一批青贮饲料的样品。定量巧克力片的量（每新鲜物质 0.44%），并对可用批次的巧克力片（69.7 毫克/100 克新鲜物质）进行可可碱分析。由于巧克力摄入量与观察到的迹象之间可能存在联系，因此除了优化 TMR 外，建议立即停止使用巧克力片，即增加能量密度。尽管发病期间可可碱的摄入量未知，反刍动物中可可碱的毒性信息有限，但我们怀疑在这种情况下喂食巧克力会导致包括奶牛突然死亡在内的所有迹象。