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82.
Effects of niacin and whole cottonseed on ruminal fermentation, protein degradability, and nutrient digestibility 总被引:1,自引:0,他引:1
J L Horner C E Coppock J R Moya J M Labore J K Lanham 《Journal of dairy science》1988,71(5):1239-1247
Four mature nonlactating Holstein heifers fitted with ruminal and duodenal cannulae were used to investigate in vivo effects of niacin and whole cottonseed. Each heifer was assigned randomly to a treatment in a 2 X 2 factorial arrangement of treatment sequences within a 4 X 4 Latin square design. Heifers were fed isonitrogenous complete mixed rations individually twice daily. Diets contained corn-soybean meal concentrate, corn silage, chopped coastal bermudagrass hay, plus 1) 0% niacin and 0% whole cottonseed, 2) 0% niacin and 15% whole cottonseed, 3) .07% niacin and 0% whole cottonseed, or 4) .07% niacin and 15% whole cottonseed. Dry matter consumption, ruminal pH, ruminal ammonia and VFA concentrations, microbial N production, and DM and ADF digestion were not affected by treatment. Numbers of ruminal protozoa and RNA concentrations were reduced with whole cottonseed feeding and increased by addition of niacin. Whole cottonseed increased molar percentages of acetate while depressing propionate. Niacin supplementation resulted in greater digestion of both CP and NDF. Ether extract digestibility was highest in heifers fed whole cottonseed. Fiber digestion was not affected by whole cottonseed feeding. 相似文献
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The evolution of stress corrosion cracks from pits is important in many industrial applications but continues to be a challenge in both measurement and prediction. Life prediction in these circumstances has to account for pit growth kinetics, the conditions for the transition from pits to cracks, and the growth rate of cracks in the short and long crack domain. An example of importance is the performance of steam turbine rotors in power generation. Although stress corrosion failures are comparatively rare, the consequences can be severe and occasionally catastrophic. Consequently, considerable effort is being focused on evaluating the effect of operational variables on pitting and crack growth and in developing an improved basis for structural integrity assessment. A preliminary mathematical model based on deterministic equations with statistically variable input parameters was developed for simulating the evolution of the pit depth distribution at different exposure times, and the transformation to stress corrosion cracks was based on the Kondo criteria. The model predicted some features of the damage well but recent novel measurements of the evolution of stress corrosion cracks from pits combined with finite element analysis of the strain distribution suggest that the transition from a pit to a crack is more complex than can be accounted for by the Kondo approach. 相似文献
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<正>本期重点:1使用仿制图章工具2转换黑白影调和调整反差3调整画面影调与色彩4调整高光与增加细节5使用蒙版工具强化色彩和反差6调整构图与使用可选颜色7使用自由变换与调节曲线一张优秀的照片如何脱颖而出?是什么让它显得与众不同?如果你需要建议让自己的照片变得出色,我们的专家很乐意在此提供 相似文献