Hart S P, Polan C E
J Dairy Sci. 1984 Oct;67(10):2356-68. doi: 10.3168/jds.S0022-0302(84)81584-2.
With a five-point radial response design, a control group, and several single factor points, effects of dietary sodium bicarbonate (0 to 4.5%) and disodium phosphate (0 to 2.0%) on calf growth, ruminal fermentation, ration digestibility, and rate of passage of liquid and particulate digesta were studied. Growth and intake data were collected age 7 to 14 wk. Rumen and blood were sampled three times. Digestion and rate of passage trials were during age 16 wk. Gains were not affected significantly but were maximized between 1 and 2% sodium bicarbonate and 0% disodium phosphate. Dry matter intake, feed efficiency, dry matter digestibility, volatile fatty acid ratio, ruminal pH, and buffering capacity were not altered by buffers. Ruminal osmolality and concentration of volatile fatty acids were increased by buffers. Digestibility of acid detergent fiber and neutral detergent fiber tended to be higher for rations containing buffers. Dilution rate of ruminal liquid increased by 40% with 2.0% sodium bicarbonate and .75% disodium phosphate, and ruminal volume was decreased. Passage rate of particulate digesta was increased by a similar amount.
采用五点径向响应设计、一个对照组和几个单因素点，研究了日粮中碳酸氢钠（0%至4.5%）和磷酸二钠（0%至2.0%）对犊牛生长、瘤胃发酵、日粮消化率以及液体和颗粒性食糜通过速率的影响。在7至14周龄时收集生长和采食量数据。对瘤胃和血液进行了三次采样。消化和通过速率试验在16周龄时进行。增重未受到显著影响，但在碳酸氢钠含量为1%至2%且磷酸二钠含量为0%时达到最大值。缓冲剂未改变干物质采食量、饲料效率、干物质消化率、挥发性脂肪酸比例、瘤胃pH值和缓冲能力。缓冲剂提高了瘤胃液渗透压和挥发性脂肪酸浓度。含缓冲剂的日粮中酸性洗涤纤维和中性洗涤纤维的消化率往往更高。添加2.0%碳酸氢钠和0.75%磷酸二钠时，瘤胃液稀释率提高了40%，瘤胃体积减小。颗粒性食糜的通过速率也有类似程度的提高。
