Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Endophyte infected Tall fescue (Festuca arundinacea Schreb.) is the most dominant grass used for pasture in the Southeastern U.S. As a result, fescue toxicosis is a major concern. Producers need alternative forages for grazing cattle that do not have this negative aspect. The objective of this experiment was to determine the grazing behavior of cattle grazing Lakota (L) prairie grass (Bromus catharticus Vahl.), endophyte infected (E+), endophyte free (E-), and novel endophyte (Q) tall fescues. Angus-crossbred steers (279±8 kg) steers wore electronic behavior data recorders in four sampling periods, and direct visual appraisals of behavior were taken in five sampling periods during the months of May to September, 2004. Overall, during the visual appraisal phase steers grazing L spent most time (P<0.05) grazing while E+ spent the least time grazing. Overall, steers grazing E+ spent more time (P<0.05) idling than those on L, E-, or Q. Steers grazing E+ spent more time (P<0.05) standing than steers grazing Q. Steers grazing Q and E- spent more time (P<0.05) lying than those grazing E+. During the data recorder phase there were no significant differences between treatments for time spent grazing. Steers grazing E+ spent less time (P<0.05) lying and ruminating than steers grazing Q or L. Conversely, time spent standing and idling for steers grazing E+ was higher (P<0.05) than for steers grazing Q or L. These results indicate that L, E-, and Q may offer benefits to producers due to more time spent in productive activities during summer months. / Master of Science

Tall fescue (Festuca arundinacea Schreb.) and alfalfa (Medicago sativa L.) have many desirable forage attributes, are grown extensively throughout the USA, and combined form a productive pasture mixture. The objective of this research was to develop recommended management practices for alfalfa-tall fescue mixtures and compare livestock performance, forage quality, and productivity of this mixture to N-fertilized endophyte-free tall fescue. Forty-eight Angus or Angus crossbred steers were rotationally stocked on a four-replicate alfalfa-tall fescue and N-fertilized tall fescue pasture system during 2002 and 2003. Livestock gain, forage quality, and forage production were monitored throughout the seasons. Management treatments conducted within wire exclosures included defoliation height, rest period, exclosure movement, and month and were evaluated using detailed botanical composition and persistence measurements. Defoliation height, rest period, and month all affected alfalfa-tall fescue competition. Alfalfa was generally more competitive with longer rest periods and shorter heights, although results were not consistent. Alfalfa composition and persistence declined dramatically over the 2003 season due to climate, grazing management, and cultivar. Cool, high moisture conditions stimulated tall fescue growth and reduced alfalfa vigor and survival. Livestock gains were higher for pure tall fescue at one date in 2002, but higher overall for alfalfa-tall fescue during 2003. Forage quality (CP, NDF and ADF) was consistently higher for alfalfa-tall fescue during both seasons. In conclusion, both alfalfa-tall fescue and N-fertilized endophyte-free tall fescue produce productive pastures and high ADG in beef steers in Virginia, but continued management research is required to maintain the alfalfa component of this mixture. / Master of Science

Graduation date: 1994

Dissertation (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

The objective of this study was to determine the effects of feeding endophyte-infected tall fescue seed to Angus steers during the stocker phase on beef shelf life. Endophyte-infected tall fescue seed had no effect on pH, TBARS, activity of superoxide dismutase and metmyoglobin reductases, and sensory attributes of strip loin steaks or patties (P >= 0.082). However, E+ patties had 0.5% more DMb (P = 0.017) and 27% greater redness (a*) on d 5 of display (P < 0.001). Retail display of steaks decreased lightness (L*), redness, oxymyoglobin percentage (OMb), and MRA from 45.01, 32.60, 67.61%, and 9.54 µM/min/g on d 0 to 40.11, 21.83, 48.95%, and 2.30 µM/min/g, respectively on d 7 (P <= 0.001). Retail display of patties decreased L*, OMb, and, MRA from 52.30, 64.04%, and 5.56 µM/min/g on d 0 to 48.88, 58.5%, and 2.16 µM/min/g, respectively on d 5 (P <= 0.001).

Two experiments were conducted to determine the efficacy of supplemented feedstuffs to improve the performance of cattle consuming fescue-based rations. The objective of the first experiment was to evaluate growth and reproductive characteristics of heifers consuming endophyte-infected (EI) fescue seed with or without sodium bicarbonate supplementation. Forty-eight heifers (8 mo; BW = 268 ± 24 kg) were utilized in a 2 x 2 factorial design. Treatments were either high-EI fescue seed without sodium bicarbonate (E+B-), high-EI fescue seed with sodium bicarbonate supplementation (E+B+), low-EI fescue seed without sodium bicarbonate (E-B-), or low-EI fescue seed with sodium bicarbonate supplementation (E-B+). At d 56, G:F (P= 0.084) and ADG (P = 0.071) tended to be improved for heifers fed E+B+. By d 84 bicarbonate supplementation tended to decrease ADG (P = 0.087). Bicarbonate supplementation ameliorated the negative effects of E+ at 28 d, but by d 84 negatively impacted animal performance. The objective of the second experiment was to determine the energy content of corn gluten feed (CGF) relative to corn in forage-based beef rations. Forty-two steers (13.8 ± 0.4 mo; BW = 382 ± 8 kg) were supplemented with either corn or CGF at 0.15% (L), 0.54% (M) or 0.96% (H) BW for 63 d. Steer ADG was greater for steers supplemented with CGF relative to steers supplemented with corn (P = 0.034). Energy value of CGF relative to corn was calculated by adjusting supplement TDN in the 2016 Nutrient Requirements of Beef Cattle Model. The energy values of CGF relative to corn were 106%, 107%, and 112% for L, M, and H. / Master of Science / Tall fescue is the predominant forage in the southeast United States, and has a symbiotic relationship with an endophytic fungus, providing drought and pest resistance to the plant. However, the fungal endophytes produce toxic ergot alkaloids which can result in decreased performance when cattle consume tall fescue. Performance losses, resulting from the consumption of these ergot alkaloids, are costly and economical strategies to reduce the negative impact of endophyte-infected fescue consumption on animal performance are needed. Previous research indicates that ruminal buffering capacity and nutrient uptake may be impaired in cattle consuming endophyte-infected fescue seed. Providing a dietary buffer is a low-cost strategy that my help to improve nutrient utilization in cattle, resulting in improved animal performance. Aside from reduced performance resulting from the consumption of ergot alkaloids, forage nutrient content can vary throughout the year, resulting in situations where the animals’ nutrient requirements are not met by the forage alone. Historically, corn has been the major energy supplement used, but recent data suggest that co-products of the corn sweetener and ethanol industries have greater energy compared to corn in both feedlot and forage-based beef rations. Supplementing corn gluten feed at low levels may improve performance of cattle consuming forage-based rations without driving up the cost of production. The objective of this thesis is to evaluate two strategies to mitigate the negative effects of endophyte-infected fescue consumption on animal performance. The first experiment was conducted to evaluate the efficacy of sodium bicarbonate to mitigate the negative effects of endophyte-infected fescue on replacement heifers. Heifers were fed a basal corn silage diet. Fescue seed and bicarbonate were supplemented at 1.5 kg/day and 0.25 kg/day, respectively. After a 56 d treatment period, bicarbonate supplementation tended to improve performance of heifers fed endophyte-infected seed with bicarbonate relative to those fed un-infected seed without bicarbonate supplementation. However, by d 84 of the experiment, the benefits of bicarbonate supplementation were no longer observed. More research is needed to understand why the benefits of sodium bicarbonate supplementation were not sustained over the full experimental period. The second experiment was conducted to evaluate the feeding value of corn gluten feed relative to corn when fed to steers consuming a forage-based ration. Steers had free-choice access to fescue hay, and individual hay and supplement intake were recorded daily. Steers supplemented with corn gluten feed had greater average daily gain than steers supplemented corn. This translated to a greater energy value relative to corn for all inclusion levels, exceeding model predictions. These experiments help to shed light on low-cost solutions to improve performance and profitability for fescue forage-based beef production systems.

This research was conducted to determine the effects of temperature and competition on seedling root and shoot growth of cheatgrass (Bromus tectorum L.) and 5 collections of Idaho fescue (Festuca idahoensis. Elmer). For the temperature study, seedlings were grown in environmental chambers with 16 hours day/8 hours night, at temperatures of 5, 10 and l5°C. Root depth was weekly recorded during 9 weeks growth period. Seedlings were destructively harvested after 63 days and evaluated for root and shoot characteristics. At all temperatures, cheatgrass exhibited greater above and below-ground biomass, root depth, total root length, daily root depth rate and shoot height than Idaho fescue. Seedlings of the 5 Idaho fescue collections produced fewer roots and grew slower than seedlings of cheatgrass. As a group, the Idaho fescue collections showed similar root and shoot growth and produced more tillers than cheatgrass, except at 5°C. As temperature increased from 10 to 15 °C, shoot growth of Idaho fescue increased while that of cheatgrass was similar. For the competition study, seedlings were grown in pots in a greenhouse with planting ratios of Idaho fescue to cheatgrass of 1:0, 1:5 and 1:10, and under 2 watering regimes. Seedlings of Idaho fescue were established from transplants grown two months ahead of cheatgrass. Shoot height, tiller and leaf number were weekly recorded. Seedlings were harvested after 49 days and evaluated for aboveground dry weight. Competition from cheatgrass depleted soil moisture and reduced growth of Idaho fescue. Cheatgrass had greater aboveground dry weight and shoot height than Idaho fescue. However, Idaho fescue had greater tiller and leaf number than cheatgrass. In addition, when competing with cheatgrass, remnant Idaho fescue plants were less adversely affected in aboveground dry weight and shoot height than Idaho fescue plants from pristine areas. These results indicated that remnant Idaho fescue plants may be a different ecotype occurring in response to competition and may better tolerate the effect of the interference from cheatgrass. This information may serve as a basis for reestablishment of Idaho fescue in Central Oregon rangelands. / Graduation date: 1993

This 2-yr experiment evaluated productivity of wild-type, endophyte-infected tall fescue (E+) and novel endophyte-infected tall fescue (NE) summer stockpiled (SS) pastures and the performance of fall-calving beef cow/calf pairs stocked on each cultivar. Fescue cultivars used were KY-31 and MaxQ for E+ and NE treatments, respectively. Pregnant Simmental x Angus cows (128 total, 64 each yr) were stratified by BW, BCS, and expected calving date and then allotted to 1 of 10 pasture groups within each yr (20 groups total, 10 per treatment). Forage growth was stockpiled from April until the initiation of strip-grazing on August 31 of 2017 and 2018. Cows grazed treatment pastures for 52 d from 23 ± 14 d prepartum to 29 ± 14 d postpartum, and calved on treatment pastures. Forage quadrats were clipped from the grazed and ungrazed portions of each pasture to determine weekly forage mass. Total ergot alkaloid (TEA) concentrations were analyzed for all pastures at the beginning of the experiment and every subsequent 2 wk for E+ tall fescue. Cow BW was recorded on 2 consecutive d and BCS determined at the start and end of the experiment. In yr 2, ultrasound 12th rib fat thickness (FT) was measured at the beginning and end of the treatment period Milk production was estimated using the weigh-suckle-weigh technique at 29 ± 14 d postpartum. Initial TEA concentrations for NE (Yr. 1 = 112 µg/kg; Yr. 2 = 632 µg/kg) were decreased (P ≤ 0.01) compared to E+ (Yr. 1 = 1831 µg/kg; Yr. 2 = 2903 µg/kg). TEA concentrations for E+ pastures did not differ (P < 0.23) by sample date. However, average TEA concentrations were greater for yr 2 than yr 1(P ≤ 0.01). Fescue cultivars were not different (P ≥ 0.06) in forage CP, Ash, Ether Extract, and grazed or ungrazed forage mass. However, differences were observed (P ≤ 0.02) for ADF, NDF, and TDN by fescue cultivar. Cow BW, BCS, and FT at the beginning and end of grazing were not different (P ≥ 0.41) by treatment. Milk production was greater (P < 0.01) for cows grazed on E+. Calving date, calf BW, calf ADG were not different (P ≥ 0.65) by treatment. Neither AI nor overall conception rates differed (P ≥ 0.23) between cultivars. Performance of fall-calving cows pre-exposed to E+ was not hindered when grazed on E+ relative to NE in a SS system. / Master of Science / Wild-type, endophyte-infected tall fescue (E+) is the predominant forage of use for producers within the southeastern United States. Endophyte-infected tall fescue gained notoriety due to its drought and pest resistance as well as climate adaptability. These advantages are the result of a symbiotic relationship with an endophytic fungus that has been shown to decrease in animal performance through the production of toxic ergot alkaloids. Development of improved fescue cultivars provided producers with an alternative forage, known as novel endophyte-infected tall fescue (NE), that maintains the agronomic advantages noted with E+ fescue without negative impacts on animal gain and reproductive performance. In adopting NE tall fescue, producers are faced with the financial challenge of renovating existing stands of E+ with NE fescue; leaving pastures unusable during times of normal grazing behavior. This constraint has highlighted the need to explore forage utilization and strategies that can extend the grazing period that do not require the significant cost of total renovation with NE. Fall stockpiled tall fescue has provided producers an option to extend grazing from late November through February when pasture growth ceases and hay supplementation is normally needed. However, a 60 to 90 d period between summer and fall stockpiled grazing leaves producers looking for an additional strategy to provide standing forage for their herds. Summer stockpiling (SS), is a novel grazing strategy that bridges summer and fall stockpiled grazing through proper accumulation of 25 % of total pasture to help extend producers grazing season. The objective of the current experiment is to evaluate both E+ and NE SS pastures and its effect on animal performance, forage availability, and nutritive value. Cow BW and BCS were measured at the initiation, conclusion, and before artificial insemination. Calf BW and ADG were assessed 48 h post-calving and at weaning. Ungrazed and grazed forage mass was collected weekly, while measurements of ADF, NDF, CP, TDN, ether extract, and ash were measured every 2 weeks. After a 52 d treatment period, forage mass was similar across both cultivars, with ADF, NDF, and TDN favoring E+ tall fescue. Additionally, animal performance across both E+ and NE pastures were similar, however increased milk production was observed for cows grazed on E+. This experiment helps shed light on the concept of strategic renovation. Strategic renovation can be best utilized by producers who are interested in maximizing pasture utilization through rotationally grazing E+ and NE tall fescue pastures. By following this renovation strategy, proper allocation of NE tall fescue during times of enhanced ergotism and E+ tall fescue during low thresholds will develop a more specific rotation thus decreasing renovation costs for producers when ergotism is lowest.

by Hon-ming Lam. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 193-217.