Department of Animal & Veterinary Science, University of Idaho, Moscow 83844, USA.
J Dairy Sci. 2012 Nov;95(11):6557-62. doi: 10.3168/jds.2011-4808. Epub 2012 Sep 12.
Betaine, naturally found in plants and an oxidative product of choline, is converted to acetate in the rumen, which may be used for milk fat synthesis. The objective of this study was to determine the effect of supplemental dietary betaine on milk yield and milk composition. Eighteen Holstein dairy cows (126±5 d in milk; mean ± SD) were randomly assigned to a sequence of treatments of rumen-unprotected betaine at 0, 25, 50, and 100 g/d added to a standard lactation ration in a 4×4 Latin square design. Animals were fed individually with feed intake and milk yield recorded daily. Body condition score and body weight were recorded on the last day of each period that lasted 16 d, with milk sampled on the last 2 d of each period. Milk composition was determined by a Dairy Herd Improvement Association laboratory and milk fatty acids were determined by gas chromatography. Data collected over the last 2 to 3 d were analyzed using the MIXED procedure in SAS (SAS Institute Inc., Cary, NC). Milk yield (mean ± SEM) was increased by betaine when fed at 100g/d (22.4, 22.5, 22.8, 24.1±1.19 kg/d for 0, 25, 50, and 100g of betaine/d, respectively). No effect of dietary betaine was detected on dry matter intake, feed efficiency, body weight, or body condition score. Percentages of milk fat, lactose, solids-not-fat, and somatic cell count were not altered; however, protein concentration was decreased by betaine supplementation as compared with the control (3.35, 3.28, 3.27, and 3.28±0.07% for 0, 25, 50, and 100 g of betaine/d, respectively). Daily yields of milk protein, fat, lactose, energy-corrected milk, and 3.5% fat-corrected milk did not differ with betaine supplementation. Overall, inclusion of dietary betaine at 100 g/d increased milk yield, whereas all levels of betaine supplementation decreased milk protein percent and slightly altered milk fatty acid profile. Further studies are needed to determine the ruminal fermentation characteristics and the optimum rate of supplemental betaine for dairy cows.
甜菜碱，天然存在于植物中，是胆碱的氧化产物，在瘤胃中转化为乙酸盐，可用于乳脂合成。本研究的目的是确定补充日粮甜菜碱对产奶量和乳成分的影响。18 头荷斯坦奶牛（泌乳 126±5d；均值±SD）随机分为 4×4 拉丁方设计，在标准泌乳日粮中分别添加 0、25、50 和 100g/d 的瘤胃未保护甜菜碱的顺序处理组。动物单独进食，每天记录采食量和产奶量。在每个为期 16d 的周期的最后一天记录体况评分和体重，并在每个周期的最后 2d 采集牛奶。牛奶成分由乳品 herd improvement association 实验室测定，牛奶脂肪酸由气相色谱法测定。使用 SAS（SAS Institute Inc.，Cary，NC）中的 MIXED 过程分析最后 2 至 3d 收集的数据。当以 100g/d 的剂量添加甜菜碱时，产奶量（均值±SEM）增加（0、25、50 和 100g/d 的甜菜碱分别为 22.4、22.5、22.8 和 24.1±1.19kg/d）。日粮甜菜碱对干物质采食量、饲料效率、体重或体况评分没有影响。牛奶脂肪、乳糖、非脂固形物和体细胞计数的百分比没有改变；然而，与对照组相比，甜菜碱补充剂降低了蛋白质浓度（0、25、50 和 100g/d 的甜菜碱分别为 3.35、3.28、3.27 和 3.28±0.07%）。牛奶蛋白、脂肪、乳糖、能量校正奶和 3.5%脂肪校正奶的日产量与甜菜碱补充剂无关。总的来说，添加 100g/d 的日粮甜菜碱增加了产奶量，而甜菜碱补充的所有水平都降低了牛奶蛋白的百分比，并略微改变了牛奶脂肪酸谱。需要进一步的研究来确定奶牛瘤胃发酵特性和补充甜菜碱的最佳速率。
