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Determining the optimal dietary roughage source and inclusion to decrease hydrogen sulfide in steers fed high-sulfur finishing diets

机译：确定饲喂高硫肥育日粮的最佳饲料粗饲料来源和减少硫化氢的夹杂物

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摘要

Commonly, protein and energy sources in feedlot cattle diets in the United States are co-products of the ethanol industry, such as dried distillers grains plus solubles. However, the inclusion of co-products is limited by the high sulfur content from the use of sulfuric acid in the ethanol production process. High sulfur diets have been shown to decrease cattle growth performance and may lead to sulfur toxicity. Dietary sulfate is reduced to sulfide or hydrogen sulfide by ruminal sulfate reducing bacteria. This process is pH dependent, thus increasing ruminal pH is thought to decrease hydrogen sulfide production. Previous research has shown the risk for sulfur toxicity may be decreased by increasing roughage inclusion in feedlot diets to greater than 6 to 8% of DM; however, little information is available comparing roughage sources or dietary concentrations to decrease the risk of toxicity while maintaining cattle performance. Thus, the succeeding research trials were designed to compare the impacts of two roughage sources on ruminal pH and ruminal hydrogen sulfide concentrations and to determine the effect of increasing roughage concentration on ruminal pH, ruminal hydrogen sulfide, cattle intake, and feedlot cattle growth performance. The results of the research show the source of roughage, when balanced on an equal neutral detergent fiber basis, did not differ in the ability to positively affect ruminal pH, hydrogen sulfide, or cattle intake. When evaluating the second research objective, increasing dietary roughage increased dry matter intake and decreased the rate of intake. Even though dry matter intake increased, the addition of roughage up to 17.3% of DM did not affect average daily gain or feed efficiency. This suggests there may be synergy between roughage and fibrous dried distillers grains, which allowed for greater cellulose digestion and compensated for the energy dilution of the diets. Ruminal pH also increased with the increased dietary roughage, suggesting the increased number of smaller meals positively influenced ruminal pH. In the first study, ruminal pH was measured via an indwelling bolus and increasing roughage resulted in a decrease in time spent under pH 5.4, 5.6, and 5.8. A lesser amount of time spent at decreased pH values is beneficial in decreasing the proportion of hydrogen sulfide in the rumen. Furthermore, hydrogen sulfide concentrations decreased with the increased inclusion of dietary roughage. The outcomes of both experiments suggest a strong negative correlation between ruminal pH and hydrogen sulfide, where, as ruminal pH increased, hydrogen sulfide decreased. In the first study a breakpoint at a pH of 5.6 was observed, where above 5.6, ruminal pH was no longer strongly influencing hydrogen sulfide concentrations; however, these differences may be attributed to differing experimental design in these studies. The results of both studies suggest including 7 to 8% neutral detergent fiber of either roughage source in high S feedlot cattle diets will increase ruminal pH and decrease hydrogen sulfide concentrations, thus decreasing the potential for sulfur toxicity. Further research is necessary to uncover if there are additional influences of increased roughage on ruminal hydrogen sulfide concentrations beyond ruminal pH alone.
机译：通常，在美国育肥牛的日粮中，蛋白质和能源是乙醇工业的副产品，例如干酒糟和可溶物。但是，副产物的加入受到乙醇生产过程中使用硫酸的高硫含量的限制。高硫饮食已显示会降低牛的生长性能，并可能导致硫中毒。瘤胃硫酸盐还原菌将饮食中的硫酸盐还原为硫化物或硫化氢。该过程是pH依赖性的，因此认为提高瘤胃pH可降低硫化氢的产生。先前的研究表明，可以通过将肥育场粗饲料中的粗饲料添加量提高至DM的6％至8％来降低硫中毒的风险。但是，很少有信息可以比较粗饲料的来源或日粮浓度以降低毒性风险，同时又保持牛的生长性能。因此，后续的研究试验旨在比较两种粗饲料对瘤胃pH和瘤胃硫化氢浓度的影响，并确定增加粗饲料浓度对瘤胃pH，瘤胃硫化氢，牛摄食量和育肥牛生长性能的影响。研究结果表明，在相同的中性洗涤剂纤维基础上平衡时，粗饲料的来源对瘤胃pH，硫化氢或牛的摄入量产生积极影响的能力没有差异。在评估第二个研究目标时，增加饮食粗饲料会增加干物质摄入量并降低摄入量。即使干物质摄入增加，粗饲料添加量高达DM的17.3％也不影响平均日增重或饲料效率。这表明粗饲料和纤维状干酒糟之间可能存在协同作用，这可以增加纤维素的消化并补偿日粮的能量稀释。瘤胃pH值也随着饮食粗饲料的增加而增加，表明少量进餐次数的增加对瘤胃pH值有正面影响。在第一个研究中，通过留置推注来测量瘤胃的pH值，增加粗饲料含量会减少在pH 5.4、5.6和5.8下花费的时间。在降低的pH值上花费较少的时间有利于减少瘤胃中硫化氢的比例。此外，随着食物粗饲料含量的增加，硫化氢浓度降低。两项实验的结果都表明瘤胃pH值与硫化氢之间存在很强的负相关性，其中随着瘤胃pH值的升高，硫化氢会降低。在第一个研究中，观察到pH值为5.6的断点，高于5.6时，瘤胃的pH不再强烈影响硫化氢的浓度。但是，这些差异可能归因于这些研究中不同的实验设计。两项研究的结果都表明，在高S肥育场牛的日粮中添加任何粗饲料来源的7％至8％的中性洗涤剂纤维将提高瘤胃pH值并降低硫化氢浓度，从而降低硫中毒的可能性。有必要进行进一步的研究以发现粗饲料增加对瘤胃硫化氢浓度的影响是否超过瘤胃pH值。

著录项

  • 作者

    Morine, Sara Jean.;

  • 作者单位

    Iowa State University.;

  • 授予单位 Iowa State University.;
  • 学科 Animal sciences.
  • 学位 M.S.
  • 年度 2014
  • 页码 125 p.
  • 总页数 125
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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