Location: Forage-animal Production Research2009 Annual Report
1a. Objectives (from AD-416)
Objective 1. Improve persistence, productivity, and quality of forage grasses and legumes for use in the transition zone of the Eastern and Midwestern U.S. Objective 2: Identify the biotic components and mechanisms of the animal-plant interface impacting grazing animal health and production. Objective 3: Improve animal and forage productivity of forage-based systems through optimization of grazing and preconditioning management protocols.
1b. Approach (from AD-416)
Forage systems provide low cost feed, conserve soil and water resources, and mitigate man’s impact on the environment. Limited basic biological information exists on how plant and/or fungal metabolites affect forage plant quality, persistence, and production. Even less information exists on the cross-talk mechanism between tall fescue (the predominant forage of the transition zone) and its endophyte or about the impact that forage and/or fungal metabolites have on pasture ecosystems. Additionally, basic biological information is limited on how plant metabolites affect animal performance and health beyond the production level. Fundamental information concerning how these production level effects are elicited has only recently become a focus. As such, the available information for predicting animal performance in response to plant nutrients under varying environmental, genetic, physiological status, and management conditions is of limited use. Even more problematic is the poor understanding of the effects of plant nutraceuticals and anti-quality factors on nutrient intake, metabolism and assimilation for product, health maintenance, or work by the animal. Thus, to increase the sustainability of forage-based animal enterprises, it is essential that a better understanding be developed of the fundamental biological processes underlying the interactions between the animal, plant, and environment. This Specific Cooperative Agreement (SCA), through the development and utilization of cutting-edge technologies, real world testing, and technology transfer, proposes to help decipher the complex interactions within the animal-plant-environment interface in order to improve forage production and persistence as well as forage-animal health, performance, and forage intake and utilization. Research is focused on the utilization and production of the predominant forage (tall fescue) of the transition zone and its alternatives and/or companion species. To accomplish the objectives of this SCA, a number of differing methodologies including molecular and chemical investigations of animal tissue and cellular function, nutrient flux experiments in cattle, classical animal nutrition studies, doppler ultrasonography, molecular and chemical investigations of plant/fungal metabolites and physiological function, pasture ecological studies, forage breeding and applied grazing trials, will be utilized.
3. Progress Report
This agreement is monitored by submission of an annual report, meetings with UK officials /scientists, and close collaborations between unit and UK scientists. Progress includes: A series of pure species pastures have been established at the UK Research Farm for grazing studies. Manure has been collected from the animals grazing these pastures and will be used to further validate the use of fecal samples for estimating consumption patterns. Methodology for evaluating fecal sterol and bile acid transport through soil was developed and ion exchange resin lysimeters for evaluating nutrient transport through soil were developed. Particle size analysis was completed for all soil depths sampled and aggregate stability analysis by wet sieving commenced along four, 170 meter experimental transects. The true armyworm (TAW), Pseudaletia unipuncta (Haworth), was reared on thirteen fescue cultivars (endophyte free) that differed in leaf texture with no significant increases in growth or development on soft textured cultivars compared with standard cultivars. A total of 29 endophyte-infected and endophyte-free tall fescue clone pairs were generated. These include 25 plants of tall fescue cultivar Kentucky 31 (KY31), each representing a distinct plant genotype and possessing the KY genotype of the seed transmissible endophyte, Neotyphodium coenophialum. The other 4 plants had novel endophytes. Fungicide (propaconazole) treatment of some ramets of each plant generated endophyte-free clones. Endophyte infection caused increased levels of certain amino acids, sugars and sugar alcohols in shoots and roots early in the onset of water deficit stress. Amino acids were also quantified in meadow fescue with or without endophytes that produce anti-insect loline alkaloids. Results indicated that mobilization of amino acids to young plant leaves drives high loline alkaloid production. Plots have been established with bermudagrass into existing endophyte infected pastures to determine the economics and nutrient utilization efficiencies of fescue, bermudagrass, and strip grazing corn. A bovine synaptic vesicle (SV) model was developed to study the effect of endophyte-derived compounds on SV vesicular glutamate transporter (VGLUT) function in glutamatergic neurons. SV-mediated VGLUT activity was characterized and abolished by bromocryptine. Tissues also were collected to establish mRNA and protein distribution profiles for VGLUT1, VGLUT2, VATPase, and synaptophytin in growing steers.