Tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) is a cool-season perennial grass used in pastures throughout the Southeastern United States. The grass can harbor a fungal endophyte (Epichloë coenophiala) thought to provide the plant with enhanced resistance to biotic and abiotic stress. However, the alkaloids produced by the common variety of the endophyte cause severe animal health issues resulting in a considerable amount of research focused on eliminating the toxic class of alkaloids while retaining the positive abiotic and biotic stress tolerance attributes of the other alkaloids. In doing so, very little attention has been paid to the direct influence the fungal-plant symbiosis has on rhizosphere processes. Therefore, my objectives were to study the influence of this relationship on plant biomass production, root exudate composition, and soil biogeochemical processes using tall fescue cultivars PDF and 97TF1 without an endophyte (E-), or infected with the common toxic endophyte (CTE+), or with two novel endophytes (AR542E+, AR584E+). I found that root exudate composition and plant biomass production were influenced by endophyte status, tall fescue cultivar, and the interaction of cultivar and endophyte. Cluster analysis showed that the interaction between endophyte and cultivar results in a unique exudate profile. These interactions had a small but perceptible impact on soil microbial community structure and function with an equally small and perceptible impact on carbon and nitrogen cycling in soils from rhizobox and field sites. These studies represent the first comprehensive analysis of root exudate chemistry from common toxic and novel endophyte infected tall fescue cultivars and can be used to help explain in part the observed changes in C and N cycling and storage in pastures throughout the Southeast U.S..

Many factors control, contribute to, stimulate and limit forage selection. It is apparent that cattle prefer certain cultivars compared to others. This study sought to test if cattle displayed preferences for certain cultivars over a two-year period in 2008 and 2009. Determining the effect of endophyte status on preference was another objective. Previous research showed rapid increase in the selection of preferred cultivars, i.e., diet learning. We attempted to replicate those results. Forty cultivars (34 tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) cultivars), two festuloliums (Festuca pratensis x Lolium perenne), two meadow fescue (Lolium pratense) and one meadow brome (Bromus biebersteinii), and one orchard grass (Dactylis glomerta L.)) were used to determine preference and to investigate factors contributing to preference. From this two-year study, we observed that cattle preferred certain cultivars compared to others, e.g. KYFA9819 > Latar-OG > Barfest-FL and AU-Triumph < 97TF1-EF < Seine, the most and least preferred cultivars, respectively. During drought conditions, both novel and toxic endophyte cultivars were preferred significantly (P < 0.05) to endophyte free counterparts. The cattle showed rejection of unpalatable grasses but did not clearly show learning to increase selection of desired cultivars.

Twenty-four steers were grazed on endophyte (Neotyphodium coenophialum)-infected [[Lolium arundinaceum (Schreb.) Darbysh]; E+] tall fescue (TF) and exposed to ergot alkaloids for an 106-d grazing period. Cattle were removed from pasture, placed in dry lots, and fed a non-toxic diet to evaluate changes in vascular contraction relative to time-off E+ TF pasture. Lateral saphenous veins (SV) were biopsied from steers at 0-, 21-, 42-, and 63-d off TF pasture and from 6 control steers at 0- and 63-d off bermudagrass (BG) pasture. To evaluate contractile response, biopsied SV were exposed to increasing concentrations of ergotamine in a multimyograph. Cross-sectional scans of the caudal artery were taken using color Doppler ultrasonography on 0-, 8-, 15-, 21-, 29-, 36-, 42-, and 45-d to determine artery luminal area. Contractility of SV was less for TF than BG steers on d 0, but was similar between the two treatments by d 63. Luminal areas of the caudal arteries in E+ TF steers relaxed over time and were similar to BG steers by 36 d off pastures. Results indicated that alkaloid-induced vasoconstriction in cattle grazed on E+ TF can be relaxed in 5 to 6 weeks after they are placed on non-toxic diets.

Fescue toxicosis can produce negative effects on animal weight gain and physiology. Sixty-four steers were grazed on endophyte-infected (E+) KY-31 tall fescue for 77 days in 2007 and sixty steers grazed for 86 days in 2008 to evaluate interactions with implantation of steroidal implants and concentrate feeding on performance and physiology of yearling steers. Steers were stratified by body weight for assignment to six, 3.0-ha toxic tall fescue pastures. The main plot treatment of with or without pelleted soybean hulls (SBH) were randomly assigned to pastures. Pelleted SBH were group-fed to provide daily consumptions of 2.3 kg/steer/d (as fed). Sub-plot treatments of with or without ear implantation with steroid hormone (200 mg progesterone--20 mg estradiol were assigned to groups of five or six steers within each pasture. Average daily gain in the experiment showed an additive effect of feeding SBH and implanting (P

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 28, 2007) Vita. Includes bibliographical references.

Fire, a natural disturbance, regulates species composition in Fescue Prairie. However, little is known about the contribution of different regeneration strategies in altering species composition after burning in Fescue Prairie. The present study was conducted to determine if and how fire and associated fire cues regulate species composition in Fescue Prairie through their effects on seedling recruitment. The effects of fire and various fire cues, including smoke, ash, and smoke plus ash on seedlings emerging in the field and/or from litter, 0-1 cm, and 1-5 cm layers of the soil seed banks were therefore examined. These studies were complimented by a study of testing effects of smoke originated from different plant materials on seed germination and seedling growth of species from Fescue Prairie. Chemical analyses were also conducted to determine whether different active compounds existed in smoke made from different materials, which in turn affect germination and seedling growth differently. Burning increased densities, richness, and diversity of seedlings emerging in the field. This was possibly attributed to direct fire cues of burning. Seedling densities of native forbs and non-native graminoids emerging from the soil seed bank were increased and decreased by burning, respectively. Ash and smoke plus ash increased density of forbs emerging from the soil seed bank. Species composition of seedlings emerging in the field and from the soil seed bank was altered by burning. Complex responses were observed for the effects of smoke on seedling establishment, which depended on the type and dilution of smoke solutions, as well as germination conditions. Smoke solutions partly substituted light requirement for germination of Artemisia ludoviciana. Germination of Cirsium arvense and Conyza canadensis only responded to smoke solutions at 25/15°C, but not at 10/0 °C. Diluted smoke solutions increased radical length of Artemisia ludoviciana. Karrikinolide (KAR1) was in the smoke made from prairie hay and wheat straw, but not in that made from alfalfa. This is the first report that different active compounds existed in smoke made from different materials. Highly concentrated smoke solutions made from alfalfa increased germination and radical length of Conyza canadensis, while the same concentrated smoke solutions made from prairie hay and wheat straw reduced germination of Conyza canadensis at 25/15 °C in darkness. Priming in KAR1 solutions and active fractions obtained from prairie hay and/or wheat straw increased germination of Artemisia frigida, Artemisia ludoviciana, and Conyza canadensis at certain germination conditions. In summary, fire and direct fire cues, smoke and ash specifically, stimulated recruitment of some species, especially early seral species and native forbs, contributing to potential changes in species composition of the Fescue Prairie. Different compounds existed in smoke solutions made from alfalfa as compared with those from prairie hay and wheat straw, showing different effects on seed germination and seedling growth. KAR1, the most important active compound discovered in smoke, was present in the smoke made from prairie hay and wheat straw, but was not in that made from alfalfa.

Northern bobwhite (hereafter, bobwhite; Colinus virginianus) have experienced long-term declines in population abundance throughout most of their breeding range. In 2004, the United States Department of Agriculture (USDA) authorized mid-contract management (MCM) to restore early successional plant communities in aging Conservation Reserve Program (CRP) fields. I evaluated the effects of 3 MCM regimes, including fall strip disking, fall herbicide spraying (hereafter, spray), and fall herbicide spraying in combination with spring legume interseeding (hereafter, spray-seed) on nearly 650 ha of tall fescue (Schedonorus phoenix [Scop]. Holub; nomenclature follows USDA plants database; see USDA 2010b) CRP in south-central Illinois, USA, during 2005-2008. The objectives of this study were to: 1) evaluate the compositional and structural responses of the vegetation community to MCM, 2) determine the structural vegetation and landscape composition variables that influenced adult bobwhite relative densities and brood presence in CRP, and 3) assess foraging rates and arthropod prey selection of bobwhite chicks relative to MCM. Spray and spray-seed treatments were more effective than disking at reducing tall fescue cover, increasing plant species diversity, and enhancing the structural characteristics of the plant community that are essential for nesting and brood-rearing bobwhite. Spray-seed and disked treatments increased the percentage of bare ground by burying the dead and dying vegetative biomass beneath the soil surface. However, spraying alone left large amounts of litter accumulation on the soil surface that resulted in a delay in the timing of some annual forbs to recolonize. Plant species composition in sprayed and spray-seeded fields changed from a dense, monoculture of tall fescue to a diverse assemblage of perennial grasses, annual forbs, and legumes that provided habitat for nesting and brood-rearing bobwhite. Adult bobwhite and broods responded positively to spray and spray-seed treatments in this study. Adult relative densities (i.e., number of adult bobwhite observed / ha) were higher in sprayed and spray-seeded fields than in disked and controls. The probability of higher relative densities was greater in fields with higher plant species diversity, and percentages of bare ground and legumes. Conversely, relative densities were negatively associated with higher percentages of grass cover. At the landscape scale, relative densities were positively correlated higher percentages of cropland and pastureland within a 250 m buffer of CRP fields. Sprayed and spray-seeded fields were 39.6% more likely to have broods present than control fields. Whereas disked fields were only 10.0% more likely to have broods than controls. Brood presence was positively correlated with higher percentages of bare ground and negatively correlated with higher percentages of grass cover. Human-imprinted bobwhite chicks consumed a higher abundance and biomass of arthropods in sprayed and spray-seeded fields than in disked and controls, although the abundance of arthropods available was generally highest in control and disked fields. This suggests, therefore, that bobwhite chicks foraging rates are not limited by arthropod availability, but rather, by the structure of the vegetative community and the ability of the chicks to access the food resources. Chicks consumed a higher proportion of hymenopterans, isopods, and lepidopterans than expected from nonrandom feeding indicating that they were actively selecting for particular prey. This research has added to the understanding of restoring bobwhite habitat to tall fescue CRP, and could assist USDA-Natural Resource Conservation Service personnel and other land managers in restoring and maintaining marginally diverse grassland ecosystems in CRP fields for nesting and brood-rearing bobwhite.

Alkaloid toxicities negatively impact livestock health and production and are of serious economic concern to animal industries. To date, few strategies have been developed to evaluate alkaloid levels in feed or to counteract alkaloid toxicities. The present research evaluated the applicability of imprinting technology to synthesize polymers that have potential to interact with ergot alkaloids and therefore reduce their bioavailability in the GIT. The studies also evaluated applicability of synthesized polymers for use in the ruminal environment using an in vitro ruminal fermentation model, and for the ability to ameliorate vasoconstriction using ex vivo myographic evaluations. In the first experiment, styrene-based molecularly imprinted polymer (MIP) was synthesized using ergotamine as the imprinting template and evaluated for specificity of adsorption to various ergot alkaloids. Cross reactivity with related alkaloids exists due to similarities in structure and functional groups. Both polymers (MIP and NIP) showed strong adsorption intensity and no difference was observed for estimated maximum adsorption capacity between MIP and NIP. Morphologically, MIP was highly porous with greater surface area than NIP. Solid phase extraction indicated stronger adsorption of MIP than NIP to ergot alkaloids suggesting the potential for MIP as a sorbent material for solid phase extraction (SPE) columns used for sample clean-up prior to HPLC or LC-MS/MS analysis of complex samples. In Experiment 2, methacrylic acid-based polymers were synthesized with ergotamine as a template. Among the 4 alkaloids evaluated for selectivity, adsorption difference between MIP and NIP interacted with alkaloid concentration, although differences were generally consistent across concentrations. Imprinting did not affect lysergol and bromocriptine adsorption, but resulted in higher adsorption to methylergonovine. However, there was no difference between MIP and NIP for adsorption of ergotamine. Hydrophobic interactions and H-bonding were the primary interactive forces between polymers and alkaloid adsorbents. Morphologically, MIP had greater surface area and porosity implying a larger surface for adsorption. In addition to its application as SPE sorbent, this MIP was a suitable candidate for application as a feed adsorbent to reduce the bioavailability of certain alkaloid in the gut. In experiment 3, methacrylic acid-based polymers were evaluated for their effect on in vitro ruminal fermentation. There were no interactions between polymer type and inclusion level, and no differences between polymer types for cumulative gas production or rate of gas production. Total gas production and rate of gas production were unaffected by inclusion level. Polymers did not affect total or individual VFA concentrations, ammonia-N or methane concentration at any inclusion level. However, a logarithmic increase in polymer dose level decreased the pH linearly with maximum depression of 0.24 units. This study indicated that, within the range of expected use levels, polymers were essentially inert and would not be expected to affect ruminal fermentation. In experiment 4, ex vivo myographic bioassays were used to determine the impact of polymers on ergotamine bioavailability. Responses measured in the ex vivo myographic studies had similar trend as the responses generated from in vitro isothermal adsorption studies. Results of that study also showed that ex vivo myographic responses could be predicted from in vitro isothermal adsorption studies with more than 80% accuracy. These studies indicate that synthetic polymers are potentially effective adsorbents to mitigate ergot toxicity with little evidence of substantial differences between MIP and NIP.

Pastures have been typically dominated by monocultures, only allowing herbivores access to one food type with unbalanced nutrient content and in some instances with single plant secondary compounds (SCs), which can be toxic if ingested at high concentrations. By establishing diverse pastures animals can select from a variety of plants with different concentrations and types of nutrients and SCs. The objectives of my study were to (a) determine if the type of plant diversity - tall fescue with either tannin-containing sainfoin or saponin-containing alfalfa − affects cattle preferences for these forages, (b) evaluate how readily fall-born calves reach finish body condition on these grass-legume pastures, and (c) determine the effects of sainfoin/tall fescue versus alfalfa/tall fescue pasture on meat quality and consumer acceptance. Foraging behavior, body weight, and pasture biomass before and after grazing was monitored when cattle strip-grazed 3 replications of 2 treatments repeated for 2 years (from May through September 2010 and from June through September 2012). Animals were allowed a choice between tall fescue and sainfoin [SAN] or alfalfa [ALF]) applied randomly in strips (fescue, legume, or fescue-legume mixture). No differences in average daily gains (~ 1 Kg/day) were detected between the 2 groups of cattle. I used scan samples at 5-min intervals from 0730 to 0930 to record foraging behavior. Animals spent most of the time grazing legumes and scans on legumes increased from the beginning to the end of the study. Scans and assessments of pasture biomass removal revealed greater use of sainfoin than alfalfa, whereas cattle in the ALF treatment removed more fescue than cattle in the SAN treatment. The presence of tannins in sainfoin likely contributed to these effects. Beef carcasses were very lean (select or standard quality grade), with 4-6% mean fat content. There were no differences between treatments regarding meat color, oxidative stability, fatty acid analyses, or consumer acceptance. Only 2 volatiles (nonanoic and decanoic acids) were greater in meat from the ALF treatment. Thus, cattle offered choices reached finish body weight at pasture and incorporated fescue into their diets even when legumes were available. The type of legume influenced foraging behavior but this effect did not impact animal performance, meat quality, or consumer acceptance.

The objective of this study was to determine the effects of feeding endophyte-infected tall fescue seed to Angus steers on average daily gain, carcass characteristics, ergovaline concentration, lipid oxidation, hepatic enzyme activity, metmyoglobin reductase activity, and mitochondrial lipid composition. Animals were blocked into light, medium, and heavy body weight groups and were randomly assigned to either a KY31 seed treatment (6796 ppb ergovaline; 20 MUg/kg BW; E+; n = 6) or a KY32 control (< 100 ppb; E-; n = 6). There was a 2-way treatment × time interaction effect on ADG (P < 0.001). The E+ steers gained 0.56 kg/d less than the E- steers from d 0 to 14 (P < 0.001) until d 56 (ADG difference = 0.27 kg/d; P = 0.007) but both group had similar ADG from d 70 till the end of the feeding period 2 (ADG = 0.53 kg/d; P > 0.070). No difference in carcass characteristics were found between the E+ and E- steers by at the time of ultrasonography (P >= 0.120) or at harvest (P >= 0.199). In both period 1 and 2, there was a 2-way treatment × time interaction for ergovaline concentration in blood (P = 0.002 and 0.022, respectively). Infected tall fescue seed did not change d-3 hepatic enzyme activity in both feeding periods (P = 0.149 to 0.645). In period 1, thiobarbituric acid reactive substances, primarily consisting of malondialdehyde (MDA), were greater in blood serum of E+ steers than E- steers (6.56 MUM vs. 2.56 MUM; P = 0.048). An overall increase in MDA from d 0 (2.39 MUM) to d 3 (7.59 MUM) was also observed (P = 0.049). There was no effect of endophyte infected tall fescue seed on metmyoglobin reductase in longissimus thoracis (4.82 MUM/min/g in E- muscle vs. 3.93 MUM/min/g in E+ muscle; P = 0.484. There was no treatment effect on mitochondrial lipid composition (P >= 0.094), including phospholipids and fatty acids.