In a cross-over design, eight rumen cannulated dairy cows were used to explore the industry-recommended method for dietary transition to fodder beet (FB: Beta vulgaris L.) on changes to rumen fermentation and pH, milk production, dry matter intake (DMI) and the risk of subacute ruminal acidosis (SARA) during early lactation. Cows were split into two groups and individually allocated a ryegrass (Lolium Perenne L.) and white clover (Trifolium repens L.) diet (HO) or the same herbage supplemented with 6 kg DM/cow of harvested fodder beet bulbs (FBH). Dietary adaptation occurred over 20 days consisting of: stage 1: gradual transition to target FB intake (days 1–12, +0.5 kg DM of FB/d); stage 2: acclimatization (days 13–17) and stage 3: post-adaption sampling (days 18–20). Response variables were analyzed as a factorial arrangement of diet and stage of adaption using a combination of ANOVA and generalized linear mixed modelling. Dietary proportion of FB represented 22, (stage 1), 32 (stage 2) and 38% (stage 3) of daily DMI. One cow during each period developed SARA from FB and the duration of low pH increased with FBH compared to the HO treatment (p < 0.01). Rumen concentrations of lactic and butyric acid increased with FBH but concentrations of acetate, propionate and total volatile fatty acids (VFA) declined by 9.3% at day 20, compared to the HO treatment (p < 0.01). Treatments did not affect milk production but total DMI with supplemented cows increased during the final stage of adaptation and feed conversion efficiency (FCE kg milk/kg DM) declined with the FBH treatment. The occurrence of SARA in 25% of animals fed FB suggest it is a high-risk supplement to animal health and further evaluation of industry-recommended methods for feeding FB at the individual- and herd-scale are needed.

中文翻译：

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在采摘的甜菜球茎上补充春季牧场，可以改变瘤胃发酵，并增加早期泌乳期亚急性瘤胃酸中毒的风险。

在交叉设计，八瘤胃插管的乳牛进行了用来探索膳食过渡到饲料甜菜业界推荐方法（FB：甜菜L.）上变为瘤胃发酵和pH，奶产量，干物质摄取量（ DMI）和早期哺乳期亚急性瘤胃酸中毒（SARA）的风险。牛被分成两组并分别分配一个黑麦草（黑麦草L.）和白三叶草（白三叶L.）饮食（HO）或相同的牧草，补充每公斤6 kg DM的收获的饲料甜菜鳞茎（FBH）。饮食适应发生了20天，包括：第1阶段：逐渐过渡到目标FB摄入量（第1-12天，+ 0.5 kg DM FB / d DM）；第2阶段：适应环境（第13-17天）和第3阶段：适应后采样（第18-20天）。使用方差分析和广义线性混合模型相结合的方法，将反应变量分析为饮食的因素安排和适应阶段。FB的饮食比例代表每日DMI的22（第1阶段），32（第2阶段）和38％（第3阶段）。与HO处理相比，FBH在每个时期都有一头牛从FB中产生SARA，低pH的持续时间随着FBH的增加而增加（p<0.01）。与HO处理相比，FBH的瘤胃乳酸和丁酸浓度增加，但乙酸，丙酸酯和总挥发性脂肪酸（VFA）的浓度在20天时下降了9.3％（p <0.01）。处理并没有影响产奶量，但是在适应的最后阶段，补充奶牛的总DMI增加了，FBH处理的饲料转化效率（FCE kg牛奶/ kg DM）下降了。25％饲喂FB的动物中SARA的出现表明这是对动物健康的高风险补充剂，需要进一步评估行业推荐的以个体和畜群规模饲喂FB的方法。