xt7tb27ps927 https://exploreuk.uky.edu/dips/xt7tb27ps927/data/mets.xml Kentucky Agricultural Experiment Station Kentucky Agricultural Experiment Station 1998 journals English College of Agriculture, University of Kentucky, Lexington, Kentucky Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station The Kentucky Agricultural Experiment Station 111th Annual Report 1998, June 30, 1999 text 2009ua018 The Kentucky Agricultural Experiment Station 111th Annual Report 1998, June 30, 1999 1998 1998 2022 true xt7tb27ps927 section xt7tb27ps927 The Kemmcficy ’ Agricuiéwzzl Expéi‘imem Siaffan 111.1 Annual Report 1998 4 Ceiiage cf Agricultugé" ' ~ Univsrsity Of Kannada “ Lexingmn; Kentucky £0346 The Kentucky Agricultural Experiment Station 111m Annual Report 1998 College of Agriculture University of Kentucky - Lexington, Kentucky 40546 To His Excellency, The Honorable Paul Patton Governor of Kentucky 1 herewith submit the one hundred and eleventh annual report of the Kentucky Agricul— tural Experiment Station for the period ending December 31, 1998. This is done in accordance with an act of Congress, approved March 2, 1887, entitled, “An act to establish Agricultural Experiment Stations, in connection with the Agricultural Colleges established in the several states under the provisions of an act approved July 2, 1862, and under the acts supplemen— tary thereto,” and also the act of Kentucky State Legislature, approved February 20, 1888, accepting the provisions of the act of Congress. Very respectfully, flay/m C. Oran Little, Director Lexington, Kentucky June 30, 1999 Contents Purpose .................................................................................................................... 7 Agricultural Economics .......................................................................................... 9 Agronomy .............................................................................................................. 1 1 Animal Sciences .................................................................................................... l3 Biosystems and Agricultural Engineering ............................................................ 15 Entomology ........................................................................................................... l7 Forestry .................................................................................................................. l9 Horticulture and Landscape Architecture ............................................................. 21 Nutrition and Food Science ................................................................................... 23 Plant Pathology ..................................................................................................... 25 Regulatory Services .............................................................................................. 27 Rural Sociology ..................................................................................................... 30 Veterinary Science ................................................................................................. 32 Robinson Station ................................................................................................... 34 Publications ........................................................................................................... 36 Financial Statement ............................................................................................... 51 Staff ....................................................................................................................... 52 AS wealt searc] struct Grant Th viding than ] cultur technl and i1 perf01 have: ers, ir devel‘ Re ment sand, 1998 Ef studi( ers at facili of the C: all re C4 Beef ages S( U: farm ment farm A1 catio tion ] swim A‘ is th< Purpose of the Kentucky Agricultural Experiment Station Ha Land Grant institution, the University of Kentucky is responsible for serving the people of the Common- wealth of Kentucky. The College of Agriculture, with its re- search, teaching, and extension activities, has developed a structure and organization to provide the mandated Land Grant services in agriculture and related areas. The Kentucky Agricultural Experiment Station has been pro— viding research results to farmers and rural residents for more than 100 years. The continued advancement of Kentucky agri- culture attests to the benefits of applying new knowledge and technology. Much of the research leading to increased quantity and improved quality of Kentucky’s agricultural output was performed by the Experiment Station. College researchers also have successfully addressed problems of agribusiness, consum- ers, international trade, food processing, nutrition, community development, soil and water resources, and the environment. Although much Experiment Station research has imme- diate application to agricultural and natural resource-related problems, scientists are also involved in basic research, gen— erating new information to help solve present and potential problems. The ability of Kentucky producers to be competi- tive in domestic and world markets requires an expanded base of knowledge in emerging areas of research applicable to agriculture, food, and natural resources. This Annual Report summarizes Experiment Station re— search highlights for 1998. Lists of the faculty, research projects, and publications completed during the year are also provided. The research programs of the Kentucky Agricultural Ex- periment Station have benefited Kentucky’s agriculture over the past century, and the results of present and future research will continue to serve Kentucky’s primary industry. Statewide Research Research activities of the Kentucky Agricultural Experi- ment Station were conducted at Lexington, Princeton, Quick— sand, and Owenton and in counties throughout the state in 1998. Efforts are constantly made to ensure that the research studies have application to the problems of all Kentucky farm— ers and other clientele groups. Locations of the experimental facilities provide conditions representative of most sections of the state. Campus — Laboratories and specialized equipment for all research program areas. Coldstream — Maine Chance — Spindletop Farms — Beef and dairy cattle, poultry, horses, sheep and swine, for— ages and grain crops, tobacco and turf. South Farm — Fruits and vegetables, ornamentals. UK Animal Research Center (Woodford County ) — This farm was purchased in late 1991 as a location for develop- ment of state-of-the-art food animal research programs. The farm is in Phase I of development as a research facility. At Princeton (Caldwell County) the Research and Edu- cation Center facilities and the West Kentucky Substa- tion Farm are devoted to research on grain crops, beef cattle, swine, fruits and vegetables, forages, and tobacco. At Quicksand (Brent/rift County) the Robinson Station is the location of research on fruits and vegetables, orna- 1 University of Kentucky, Lexington 2 Research and Education Center and West Kentucky Substation Farm, Princeton 3 Robinson Station and Forest, Quicksand 4 Eden Shale Farm, Owenton mentals, forages, grain crops, tobacco, and wood utilization. Quicksand is also the headquarters of Robinson Forest, which spreads over parts of Breathitt, Perry, and Knott coun- ties and is the site of forestry and watershed management research. The Eden Shale Farm, located in Owen County near Owenton, is where experimental and demonstration studies are conducted on forage crops, tobacco, fruits and vegetables, and beef management. Re jects i comp; financ ogy, 1i Polic Risk P0 form. used 1 dies f: cause risk n plant: also 1 be wi Envil A could tional has bi marki gases contn 21 mai carb( (BMl ing tl Dair} E) comp lie in‘ is tha ity. T perce data Each volat ence cally Agricultural Economics Research in Agricultural Economics involves diverse sub- jects including crop insurance, environmental policy, dairy compacts, farm profitability, farm safety, input management, financial analysis, telecommunications, information technol- ogy, labor constraints, and credit issues. Policy Research Risk Policy makers are once again debating crop insurance re- form. Research conducted at the University of Kentucky was used to inform that debate. It showed crop insurance subsi— dies favor high-risk regions and high-risk farmers, which has caused crop production to shift from the low—risk to the high- risk regions. In addition, there are up to three percent more planted acres due to risk management subsidies. Prices are also likely to be two to three percent lower than they would be without the risk subsidies. Environment A new area of research examined the role U.S. farmers could play in reducing greenhouse gases, a major interna— tional objective. Using the market to trade sulfur emissions has been a large success in the US. Likewise, a worldwide market for carbon emissions could help reduce greenhouse gases in a more cost-effective fashion than command and control systems. U.S. farmers could be big winners from such a market as they are uniquely positioned to sequester more carbon by adopting more Best Management Practices (BMPs). Adopting more BMPs has the dual effect of clean- ing the global and the local environment. Dairy Compacts Existing policy allows the formation of interstate dairy compacts only if they are deemed to serve a compelling pub— lic interest. One argument used in support of dairy compacts is that consumers will benefit from greater retail price stabil— ity. This study estimated demand systems for whole, two percent, one percent, and skim milk using weekly scanner data at the national level from March 1996 to June 1998. Each system includes one of four measures of retail price volatility. The results suggest that price volatility can influ— ence fluid milk demand but does not necessarily systemati- cally depress demand. Enhancing Farm Profitability and Management Efficiency Farm Safety Farm owner-operators and workers tend to make safety decisions from a subjective cost/benefit perspective. Research indicates that farm workers do not recognize the direct and indirect costs associated with work-related injury and thus are not making safety decisions on an accurate basis. Injury prevention interventions requiring farm worker participation relate safe work practices and safety improvements to the economic viability of the farm. Nonuniform Inputs An econometric model was developed to improve opti— mal farm decision-making when inputs are nonuniformly applied to a field such as irrigation water from a sprinkler system, pesticides from an airplane, or manure from a spreader. There are important implications for input-cost minimization and precision agriculture in Kentucky. Financial Analyses Two mistakes in a top—tier econometrics methodology jour— nal were corrected. The newly developed econometric meth— odology permits the economist to analyze time series and cross—sectional data in a simultaneous-equations system. These methods can easily be used to properly analyze the relative financial economic performance of farms in our Kentucky Farm Business Management database or the rela- tive competitiveness of counties in the databases maintained by the TVA Rural Studies Center. Economic Development Telecommunications The ability to use advanced telecommunications technol— ogy is critical to the well—being of rural areas. TVA Rural Studies contracted two research projects to this end. The first looked at the availability and quality of central office switches. It found that while most rural areas are served by digital switches, the capacity in terms of advanced services those switches provide tended to be less than in urban areas. Furthermore, any telecommunications user farther than ap— proximately three miles from the switch was unable to re— ceive and use digital (including data processing) services without purchasing expensive “dedicated lines.” Thus, many rural areas are not able to enjoy the full benefits of advanc— ing technology. The second report provided an overview of other barriers that keep rural areas from gaining access and using advanced telecommunications. These barriers include market—based constraints, regulatory constraints, and end—user constraints. Various ways that rural communities can surmount these obstacles were discussed. Information Technology A study was conducted to shed light on the extent to which information technologies such as computers, the World Wide Web, telephones, ATM cards, etc., can be used to enhance the delivery of public services into rural communities. The study found that rural residents, the poor, and the elderly were significantly less likely to use such technologies in Kentucky, raising questions about the feasibility of basing the delivery of government services on these technologies in the future. Rural Southern Labor There is great concern that areas in the rural South will be unable to compete in the new economy. Advancing technol- ogy, globalization, and changes in government policy such as welfare reform all present the rural South with a new set of challenges. Unfortunately, the region does not appear wholly prepared to respond. Poverty, racial discrimination, and poor education all hamper the performance and poten- tial of many workers in the region. These findings and oth- ers were presented at a research conference co—sponsored by TVA Rural Studies. Rural Credit In most rural places, the bank system provides adequate access to debt capital. However, the availability of equity IO capital continues to be a problem. This study found there is no single model for a rural equity institution. Key model determinants included the institution’s goals, what weight to put on rate of return versus economic development, target— ing decisions, choice of instruments, and exit strategies. Further, the study found that utility cooperatives—elec- tric and telephone—are viable providers of equity invest— ments in rural America. This research identified several ad- vantages cooperators can offer including access to capital and long-term development interest. Thus, utility coopera— tives may be an underutilized resource for rural communi- ties and could provide important start-up capital for economic development projects. Research Projects Agricultural Industrialization and Globalization: Implications for Ru- ral Economies — S. Goetz, D. Debertin, R. Fleming, A. Pagoulatas An Evaluation of International Markets for Southern Commodities — M.A. Marchant, M.R. Reed Analyzing Impacts of Structure of US. Agriculture on Structure of Nonfarm Rural Communities — D. Debertin, S. Gael: Analyzing the Future International Competitiveness of the US. Food Industry — M.R. Reed, M.A. Marc/tam, L. Mather Economic and Environmental Impacts of Water—Quality Protection Policies on Kentucky Agriculture — H. Hall, J.R. Skees Evaluation of Public Policy Alternatives Designed to Help US. Cash— Crop Farmers Manage Risk — J.R. Skees, H. Hall Financing Agriculture and Rural America: Issues of Policy, Structure, and Technical Change — D. Freshwater Fruit and Vegetable Supply—Chain Management, Innovations, and Competitiveness — T. Woods Impacts of Trade Agreements and Economic Policies on Southern Agriculture — M.A. Marc/1am Rural Economic Development: Alternatives in the New Competitive Environment —S. Gaerz, D. Freshwater Agronomy The Department of Agronomy conducts research in four criti- cal areas: soil science, crop ecology and management, crop ge— netics, and plant biology. Our work ranges from crop produc- tion tests in field plots to cutting—edge laboratory studies. We strive to improve the yield and quality of crops while conserv- ing soil and water resources. Examples of interesting and p0- tentially important research during 1998 are described below. Plant Breeding - A new burley tobacco variety, KY 910, will be available to producers in 1999. KY 910’s distinguishing character- istics are high resistance to the common strain of black shank and medium resistance to other black shank strains. Because of its moderate yield potential, KY 910 will be most beneficial to burley producers who must grow their crops on black shank-infested land. ' A new soft red winter wheat variety, KY 86C—6l-8, was released by the Kentucky Agricultural Experiment Station in 1998 for its yield potential, disease resistance, winter- hardiness, early maturity, and outstanding milling quality. . Approximately 40 experimental populations of endophyte- free tall fescue were synthesized during 1998. Some of these represent the fourth cycle of selection and are in the early stages of seed increase for possible cultivar release in the near future. 0 In 1998, the Kentucky Agricultural Experiment Station released soybean line KY 91-1214 as variety 7499, with marketing rights assigned to UniSouth Genetics. This is a late group IV variety released for its high yield in full— season and double—cropped environments in Kentucky. It is resistant to southern stem canker. 0 Variety testing programs are an essential resource for Ken- tucky grain crop producers. Hybrid corn performance tests were conducted at seven Kentucky locations for feed grain hybrids and at three Kentucky locations for high—oil hy- brids. Forty-eight wheat varieties and several hundred wheat breeding lines were evaluated at seven locations. One hun— dred and thirty soybean varieties and breeding lines were also evaluated in yield trials grown at two locations. Crop Production ° More than 4,000 corn grain samples were evaluated for chemical composition in the Corn Grain Quality Labora— tory, a cooperative effort with the Kentucky Corn Grow— ers Association. ' Corn row width and plant population studies confirmed that 20-inch rows do not give additional corn yield re- 11 sponse in Kentucky over 30-inch rows. Plant population responses are more consistently observed, with economic yield responses highest at 26,000 to 28,000 plants per acre in 30—inch rows. Kentucky growers should soon have opportunities to con- tract production of novel soybean varieties at premium prices. Designer soybean varieties include high oleics (for vegetable oils), high sucrose (for soy milks), and low satu— rates (for salad dressings). Quality of grain produced un— der Kentucky conditions has been quite good, and yields have been comparable to those obtained elsewhere. Estimated losses associated with storage and feeding of the 4.8 million—ton hay crop in Kentucky exceed 40 percent of the crop and $100 million in value. Wrapped, baled silage represents a viable alternative to current practices. Our re— search shows that high bale density, moistures between 45 and 65 percent, minimum delay before wrapping, and main— tenance of anaerobic conditions during storage are impor- tant management considerations. Perennial broadleaf weeds (dicots) such as common pokeweed, trumpet creeper, and honeyvine milkweed have become more prominent in corn and soybean fields that are subjected to continuous no-till production practices. On-farm studies have been conducted in no-till corn and soybean fields to evaluate weed management tactics for these problem species. Maleic hydrazide (MH) residues on tobacco continue to be a concern. Newly developed sucker control programs can reduce residues, yet improve sucker control and in— crease yields. Random testing throughout Kentucky now indicates a positive trend in residue levels. Plant Biotechnology - Solanaceous plants like tobacco respond to pathogens by the production of antimicrobial compounds. Recent in— vestigations of this response have identified specific mo- lecular elements important for control of defense gene expression. Rapid curing of tobacco minimizes the accumulation of tobacco-specific nitrosamines (TSNA) and will reduce the amount of these compounds in smoke. Our continuing studies of TSNA accumulation have shown that com- pletely covering tobacco with plastic in outside curing structures will increase TSNA levels in comparison to conventional structures. Research completed on soybean transformation has re- sulted in more efficient gene transfer of useful foreign genes from other organisms into soybean. During the year we successfully introduced a protein-modifying gene, a fatty acid—modifying gene, and a herbicide—tolerance gene into adapted soybean cultivar backgrounds. We are developing new methods for expressing multiple genes in plants. We have tested a strategy for simulta— neously expressing several enzymes in different subcel— lular compartments of plants. We have successfully ap— plied this technology to express antibodies in transgenic plants. Research showed that the toxic acyl-loline alkaloids in endophyte-infected tall fescue ingested by cattle were con— verted into harmless substances during digestion and then excreted. Conversely, the toxic ergopeptide alkaloids were apparently converted into potent derivatives, such as ly- sergic acid amide. We have discovered a novel mechanism for elongation of both branched and straight medium—chain fatty acids in plants. The novel mechanism appears to be restricted to trichome glands. Environmental Studies Laboratory experiments with large undisturbed soil blocks will enhance our ability to classify soils according to trans— port rates and aid in the development of best management practices for agricultural chemicals applied to partially saturated soils. Poultry litter applied to no-till soils could result in in- creased runoff of fecal bacteria. We examined the effect of residue level and no-tillage on runoff of fecal bacteria from soils during rainfall. Total fecal bacteria losses (but not bacterial concentration) were reduced in no—tillage because surface runoff was minimized and infiltration was maximized. Carbon storage in soils is important to forest ecosystems. Analysis of digital soil survey data has produced an esti- mate of soil carbon storage in forested landscapes of south— eastern Kentucky. More detailed examination of carbon storage will be used to investigate its possible response to changing management practices or climate. Laboratory and field leaching experiments with metal- contaminated soils indicated that colloids in flushing so- lutions may enhance desorption and remobilization of the metals. These findings point to greater potential for groundwater contamination at some sites but to opportu— nities for more effective remediation at others. Research Projects Amount and Quality of I-Ierbage Ingested by Cattle Grazing Tall Fes— cue Clover Grasslands —— CT Daugherty Analysis omeNA Polyadenylation and Metabolism in Plants —A.G. Hunt 12 Animal Mantirc and Waste Utilization Treatment and Nuisance Avoid- ance for a Sustainable Agriculture — G.L. Cromwell, J.H. Grove Breeding Improved Varieties of Wheat, Oats, and Barley for Kentucky — DA. Van Sanford Characteristics of a Plant Poly (A) Polymerase — A.G. Hunt Characterization, Classification, and Use Interpretations of Kentucky Soils —— A.D. Karat/rations Characterization of Phytoalexin and Sterol Biosynthetic Genes in To— bacco — J. Chappell Classifying Soils for Solute Transport as Affected by Soil Properties and Landscape Position —— E. Perfect Cloning and Heterologous Expression of Pesticide Metabolizing Cy— tochrome P450 —— M. Barrett Corn Breeding and Genetics: White Endosperm Breeding, Food Quality Inheritance, and Hybrid Performance Tests — CG. Poneleit Determining Rates of Several Nutrient Sources for Optimum Crop Production and Soil — W.0. Thom Distribution of Constituents within Tobacco Leaf— H.R. Burton, L.P. Bush Early Maturing Soybean Cropping System: Identifying Appropriate Cultivars — L.J. Grabau Effect of Tillage and Land Use on Physical and Chemical Properties of Kentucky Soils — G.W. Thomas, R.L. Blevins, J.A. Thompson Effects of Suckering Practices on Growth Characteristics, Yield, and Quality of Burley, Dark Fire—Cured, and Dark Air—Cured Tobac— cos — J.R. Calvert Evaluation of Burley Tobacco Varieties — J. Calvert, 3. Kennedy Evaluation of Perennial Forage Crop Varieties — R. Spitaleri Evaluation of Soybean Varieties and Breeding Lines for Use in Ken— tucky — T. w. Rfetfl'er Forage Crop Genetics and Breeding to Improve Yield and Quality — N.L. Taylor Integrated Management of Arthropod Pests of Livestock and Poultry — CT Daugherty Manipulation and Regulation of Oxylipin Formation in Plant Tissues — D.F. Hildebrand Mechanisms for Vacuolar Storage/Sequestration of Cd, Zn, Mn, Ni — GJ. Wagner Mineralogical Controls on Colloid Dispersion and Solid»Phase Spe- ciation of Soil Contaminants — R.I. Barn/rise! Multiplicative (Linear-Bilinear) Models for Genotype X Environment Interaction in Crop Cultivars — P.L. Cornelius Pest Control Strategies for Grazing Livestock Using Grass-Endophyte Associations — CT Daugherty, F.W. Knapp, L.P. Bush Phenology, Population Dynamics, and Interference: A Basis for Un— derstanding Weed Biology and Ecology — WW. Witt Plant Genetic Resource Conservation and Utilization — N.L. Taylor Regulation of C6—Aldehyde and Alcohol Formation in Plant Tissues — D.F. Hildebrand Relationship between Photosynthesis, Assimilate Supply, and the Size of the Reproductive Sink — D.B. Egli Seed Biology and Technology Investigations — D.M. TeKrony, D.B. Egli, R. Geneve, A. Downie Significance of Loline Alkaloids in Ecosystems Predominated by Grass/Endophyte Associations — L.P. Bush Soil and Crop Nitrogen Testing to Improve Nitrogen Management for Burley Tobacco — R.C. Pearce, J. G. Grove, D. C. Ditseh Somatic Cell Genetics of Crop Plants —— GB. Collins Species and Crop Management Effects on the Yield and Quality of Round Bale Silage —— M. Collins Studies of and Efforts to Engineer the Metabolism in Plant Trichomes — GJ. Wagner The Role of Ammonium—Potassium-Calcium Exchange Interactions in Regulating Nitrification Rates in Soil — V.P. Evangelou, M.S. Coyne Understanding Recombination and Modifying Its Frequency in Soy— bean and Corn — T.W. Pfet't'fer Animal Sciences Income from livestock fluctuates drastically from year to year. The past year was a harsh reminder of this fact. While some commodities fared well, others were devastated by farm gate prices. Through good times and bad, research remains an essen— tial component of successful livestock and food production. We have emphasized efficient utilization of forages, adding value to our animal products, maintaining a safe food supply, increased efficiency of production, and research methods that help ensure sustainable agricultural practices. Livestock makes up more than 50 percent of the total cash receipts from agriculture in Ken- tucky and is one of the Commonwealth’s most vital economic segments. Nonruminant Nutrition Research was conducted with a mutant corn that contained a majority of its phosphorus in an inorganic form rather than as phytic acid, which is poorly bioavailable to nonruminants. The phosphorus in low—phytate corn was three to four times as bioavailable to pigs and chicks as the phosphorus in nor- mal corn. In diets containing low—phytate corn, less inorganic phosphorus was needed to maximize performance and bone mineralization. Phosphorus excretion was reduced by 30 to 40 percent in pigs fed low-phytate corn. The bioavailability of phosphorus in meat and bone meal was found to be 85 to 90 percent for pigs. Particle size, pro— cessing temperature, and origin (bovine versus porcine) had no effect on phosphorus bioavailability. Porcine somatotropin (pST) was found to increase accre— tion rates of carcass lean tissue and whole body protein in growing pigs. Finishing pigs receiving pST required greater dietary amounts of calcium and phosphorus than control pigs. Reducing the dietary protein level and adding amino acids reduced the amount of nitrogen excretion in pigs and reduced ammonia release from their manure. Similarly, feeding a low— phosphorus diet supplemented with microbial phytase or feed- ing low-phytate corn reduced the phosphorus excretion in the manure. A by-product resulting from the process of extraction of heparin from porcine intestines was found to have excellent properties as a protein source for weanling pigs. Weanling pigs demonstrated a preference for a diet containing the by— product as one of the animal protein sources compared to a diet without it. Graded levels of five B-vitamins (niacin, riboflavin, folic acid, pantothenic acid, and B12) to a low vitamin diet im- proved growth rate and carcass lean gain in pigs. Growth rate and lean gain improved with vitamin supplementation. Potential interactive effects of chromium supplementa— tion with dietary energy level, protein level, or energy source in growing pigs were assessed. There was no effect of, or any interactions with, chromium in regard to growth rate or carcass composition. Two important environmental problems faced by the poul- try industry are excessive ammonia emissions from broiler litter and excess nitrogen in the litter. Reducing protein in- take can minimize these problems but can also result in poor growth. Three experiments were conducted feeding broiler chickens low protein corn-soybean meal diets with various supplements of essential and nonessential amino acids and additional dietary energy. The results provided information on the concentrations of essential amino acids required for optimum body weight gain and feed conversion using low protein (17 percent) diets. These can be useful in formulat— ing broiler diets that can lower litter nitrogen concentrations and ammonia levels in the broiler houses. Ruminant Nutrition Experiments were conducted evaluating the effect of small intestinal protein on intestinal digestion in ruminants. Infu- sions were used to control the amount of protein reaching the small intestine. Increasing protein supply to the small intestine increased intestinal carbohydrate disappearance and increased the pancreatic secretion of amylase. These studies suggest protein may have a regulatory role in how nutrients are assimilated in the small intestine of cattle. This informa- tion may be key in determining limitations to intestinal di- gestion and may be useful in optimizing nutrient utilization. Another effort has been the characterization and cloning of amino acid transport proteins that are expressed in the gastrointestinal epithelia, liver, pancreas, and kidney of cattle and sheep. This is novel research for ruminant species and will be used to improve the efficiency of amino acid absorp— tion and metabolism by designing diets that contain opti— mized ratios of amino acids, based on a knowledge of amino acid transporter physiology. Research with calves indicates supplementation with as little as 15,000 IU/d of vitamin A may decrease growth and vitamin E in blood. Rumen Microbiology Our rumen microbiology laboratory has confirmed the isolation of a previously unrecognized group of propionate— producing bacteria that use succinic acid as a sole carbon source. The organisms represent a new species of ruminal bacteria that appear to play a critical role in propionate me- tabolism in the rumen. Fibrous carbohydrates in plant material are an important source of carbon and energy for anaerobic bacteria inhabit- ing the digestive tract of ruminants. In addition, these carbo- hydrates are found in agricultural, municipal, and forestry waste and could serve as renewable resources for chemical production via bacterial fermentations. The hemicellulose fraction of plant fiber is comprised of pentose sugars such as xylose, but pentose utilization by anaerobes is generally not well understood. Several genes were identified that are re— sponsible for xylose metabolism in the anaerobic thermo- phile, Thermoanaerobacter etlzanolicus. A novel xylose binding protein was also characterized that could be useful in the development of thermostable biosensors. These are the first in—depth genetic studies of xylose utilization in a thermophilic bacterium and represent a significant advance- ment in the understanding of these biotechnologically im- portant organisms. The information obtained from the thermophile studies is currently being used to identify simi- lar xylose utilization genes in