Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
J Dairy Sci. 2020 Nov;103(11):10122-10135. doi: 10.3168/jds.2020-18425. Epub 2020 Sep 28.
Leftover bakery by-products (BP) from bakeries and supermarkets may serve as energy-rich ingredient in ruminant diets. The aim of the present study was to evaluate the effect of the successive substitution of cereal grains by BP on dry matter (DM) intake, milk production, and metabolic health as well as ruminal pH and eating and chewing behavior of dairy cows. Twenty-four lactating Simmental cows (149 ± 22.3 d in milk, lactation number 2.63 ± 1.38, 756 ± 89.6 kg of initial body weight) were fed a total mixed ration containing a 50:50 ratio of forage to concentrate throughout the experiment (35 d). During the first week, all cows received a control diet (without BP) as a baseline (d -7 to 0). In the next 4 wk (d 1 to 28), cows were allocated to 3 groups differing in the BP concentrations of diets [0% BP (CON), 15% BP, and 30% BP on a DM basis]. The DM intake and reticuloruminal pH were continuously measured. Blood and milk samples were taken every week, but only results from the experimental period (d 21 and 28) were used for statistical analyses, whereas results from the baseline were considered covariates. Diet analyses showed that BP inclusion increased the ether extract and sugar contents, whereby starch and neutral detergent fiber decreased. Experimental data showed that feeding BP in the diet increased DM intake. Furthermore, the cows fed 30% BP produced roughly 4 kg/d more milk and energy-corrected milk than the CON cows. The milk urea nitrogen was lower in cows fed the BP. Feeding BP reduced the blood glucose and insulin concentrations, whereas nonesterified fatty acids, β-hydroxybutyrate, and cholesterol increased linearly. Cows fed 15% BP had the shortest period of time in which ruminal pH was below 5.8, in contrast to CON cows (+188 min/d). Taken together, the results suggest that the inclusion of up to 30% BP in the diets of mid-lactation dairy cows shifted the nutrient profile from a glucogenic diet to a lipogenic diet, holding the potential to enhance performance and lower the risk of subacute ruminal acidosis in dairy cows.
面包店和超市的剩余烘焙副产品 (BP) 可以作为反刍动物日粮中的高能原料。本研究旨在评估谷物连续替代 BP 对奶牛干物质 (DM) 采食量、产奶量和代谢健康以及瘤胃 pH 值以及奶牛采食和咀嚼行为的影响。24 头泌乳西门塔尔奶牛（泌乳天数 149±22.3 天，泌乳次数 2.63±1.38，初始体重 756±89.6kg）在整个实验期间（35 天）均饲喂含 50:50 粗饲料和精料的全混合日粮。在第一周，所有奶牛接受对照日粮（不含 BP）作为基线（d-7 至 0）。在接下来的 4 周（d1 至 28），奶牛分为 3 组，日粮中 BP 浓度不同[0% BP（CON）、15% BP 和 30% BP（DM 基础）]。连续测量 DM 采食量和瘤胃 pH 值。每周采集血样和奶样，但仅对实验期（d21 和 28）的结果进行统计分析，而基线结果则视为协变量。日粮分析表明，BP 的添加增加了乙醚提取物和糖的含量，从而降低了淀粉和中性洗涤剂纤维的含量。实验数据表明，日粮中添加 BP 可增加 DM 采食量。此外，与 CON 奶牛相比，饲喂 30%BP 的奶牛产奶量和能量校正奶量增加了约 4kg/d。饲喂 BP 的奶牛的牛奶尿素氮较低。BP 的添加降低了血糖和胰岛素浓度，而非酯化脂肪酸、β-羟丁酸和胆固醇则呈线性增加。与 CON 奶牛相比，饲喂 15%BP 的奶牛的瘤胃 pH 值低于 5.8 的时间最短（每天减少 188 分钟）。综上所述，结果表明，在泌乳中期奶牛日粮中添加高达 30%的 BP 可改变营养谱，从生糖日粮转变为生脂日粮，从而有可能提高奶牛的生产性能并降低奶牛亚急性瘤胃酸中毒的风险。
