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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING SUSTAINABILITY OF FORAGE-BASED PRODUCTION SYSTEMS
2013 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 final report documents progress for this project. Milk yield of cows consuming ergot alkaloids was reduced, but after cessation of alkaloid consumption their milk yields increased to quantities above those maintained on alkaloid-free diets. Histological and molecular analyses showed that alkaloids do not affect mammary development. Sequencing of Ribonucleic acid (RNA) from mammary tissues was performed at three time points of lactation for cows consuming ergot alkaloids, and these genetic expressions will be catalogued in a searchable database. Genetic expression in Bovine cerebral and kidney tissues demonstrated adverse effects of ergot alkaloids on cellular function by their direct inhibition of specific glutamate and nucleoside transport activities. An in silico approach was used to map over 1,000 red clover genes with known genetic locations to the Medicago truncatula genome. Broad regions of similarity and the identification of numerous chromosomal rearrangements between the two genomes will be useful in studying genetic expression in forage legumes. A procedure was developed to increase the large scale extraction efficiency and partial purification of the ergot alkaloids in infected tall fescue seed to improve our ability to control amounts of ergot alkaloids exposed to digestion and absorption. RNA profiling of two clone pairs of endophyte-infected and endophyte-free tall fescue was performed to evaluate the effects of the endophyte on host plant gene expression under unstressed and water deficit conditions. A determination was made of the tiller recovery and accumulations of metabolites between three clone pairs of endophyte-infected and -free tall fescue plants under water deficit stress. A technique using near infrared reflectance spectroscopy was developed to determine grass species composition in manure from horses, which will be useful in studying relationships between species composition in the diet and pasture species composition. Differences in chemical, physical, and biological characteristics were found between soils from adjacent stands of endophyte-infected and -free fescue located at 13 sites across southeastern United States of America. Further, endophytes provide a boost in carbon sequestration by host plants. It was determined that endophytes do not affect nutrient leaching or earthworm distributions in the soil. Scientists determined that populations of herbivorous and predatory arthropods differed little among pasture grasses containing toxic and non-toxic endophytes. Armyworms grew equally well on fescue differing in leaf blade texture and their susceptibility to virus infection did not differ between armyworm feeding on smooth and spiny grass blades. Vasoconstriction occurs in horses in response to their consumption of ergot alkaloids, and is more pronounced in leg arteries than in uterine arteries. It was also determined that blood flow in the ovaries is reduced. These were the first reports that ergot alkaloids cause vasoconstriction in horses. Scientists found that ergot alkaloids do not affect weight gain of weanling horses, but there were perturbations in hormone profiles.


Last Modified: 10/21/2014
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