Feeding a total mixed ration with 50% concentrate and a mean deoxynivalenol (DON) concentration of 5.3 mg/kg DM to 13 German Holstein cows in early lactation (Myco group) resulted in alterations in the ruminal fermentation patterns (lower molar percentage of acetate and isobutyrate, higher molar percentage of valerate) compared to the 14 control cows (Period 1, 11 weeks). In the Myco group, significantly lower ruminal pH value occurred in weeks 4 and 8 and lower minimum pH values critical for developing subacute ruminal acidosis were detected. Accordingly, the net acid base excretion in the urine and the base-to-acid ratio were lower (significant in week 8 only). These effects probably resulted from a higher dry matter intake and are not related to the presence of Fusarium toxin. In Period 2, the same 27 cows plus five additional cows were divided into four groups over 18 weeks. The effects of an elevated concentrate proportion of 60% were tested with and without Fusarium toxin (Control-60, 0.4 mg DON/kg DM and Myco-60, 4.6 mg DON/kg DM) and compared to two groups fed 30% concentrate (Control-30, 0.6 mg DON/kg DM and Myco-30, 4.4 mg DON/kg DM). As expected, a high concentrate proportion significantly affected the ruminal fermentation patterns. Net acid base excretion and base-to-acid ratio did not reveal a distinct concentrate effect and the ruminal pH values were on a high level in all groups when ruminal fluids were taken after 3–5 hours of feed restriction (median between 6.8 and 7.2). Additional effects were observed on the profile of short chain fatty acids in the presence of Fusarium toxin at both concentrate levels. This indicates a switch in the microbial community due to direct mycotoxin effects and/or indirect effects of the Fusarium infection related alterations in the physico-chemical properties of the infected cereal on ruminal microbes.

中文翻译：

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受镰刀菌毒素污染小黑麦奶牛日粮中浓缩物比例影响的尿液中酸碱代谢的瘤胃发酵模式和参数

给 13 头泌乳早期的德国荷斯坦奶牛（Myco 组）饲喂含 50% 浓缩物和平均脱氧雪腐镰刀菌烯醇 (DON) 浓度 5.3 mg/kg DM 的总混合日粮，导致瘤胃发酵模式的改变（较低的乙酸盐摩尔百分比和异丁酸，较高的戊酸摩尔百分比）与 14 头对照奶牛（第 1、11 周）相比。在 Myco 组中，第 4 周和第 8 周瘤胃 pH 值显着降低，并且检测到对发生亚急性瘤胃酸中毒至关重要的较低最低 pH 值。因此，尿液中的净酸碱排泄量和碱酸比较低（仅在第 8 周显着）。这些影响可能是由于较高的干物质摄入量造成的，并且与镰刀菌毒素的存在无关。在第 2 阶段，在 18 周内，同样的 27 头奶牛加上另外 5 头奶牛被分为四组。在使用和不使用镰刀菌毒素（Control-60，0.4 mg DON/kg DM 和 Myco-60，4.6 mg DON/kg DM）的情况下测试了 60% 的浓缩物比例升高的影响，并与喂食 30% 浓缩物的两组进行了比较（ Control-30, 0.6 mg DON/kg DM 和 Myco-30, 4.4 mg DON/kg DM)。正如预期的那样，高浓缩比例显着影响瘤胃发酵模式。当在限制饲料 3-5 小时（中位数在 6.8 和 7.2 之间）后采集瘤胃液时，所有组的净酸碱排泄量和碱酸比没有显示出明显的浓缩作用，并且瘤胃 pH 值处于高水平）。在两种浓缩水平的镰刀菌毒素存在下，观察到对短链脂肪酸谱的额外影响。