Browsing by Subject "Grazing"

Now showing 1 - 5 of 5
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    Advances in Horse Nutrition and Muscle Protein Synthesis: Grazing Warm Season Annual Forages and Evaluating Muscle Protein Synthesis in Response to Leucine
    (2016-08) DeBoer, Michelle
    Warm-season grasses have the potential to provide forage in Upper Midwest pastures. The objectives of this research were to determine yield, forage nutritive value and preference of annual warm-season grasses under horse grazing. Four adult horses (Equus caballus) grazed Japanese millet (Echinochloa esculenta (A. Braun) H. Sholz) Siberian millet (Setaria italica (L.) P. Beauv.), teff (Eragrostis tef (Zucc.) Trotter) sorghum sudan BMR (Sorghum bicolor (L.) Moench), sudangrass (Sorghum sudanense (Piper) Stapf.), and annual ryegrass (Lolium multiflorum L.) at mature and vegetative stages. Forages were seeded in two separate plots utilizing a randomized complete block design with three replicates per plot. Each plot was grazed at a distinct target maturity and each maturity was grazed a minimum of three times each grazing season over a two-year period. Sudangrass was consistently the highest yielding grass (P ≤ 0.0002), producing ≥ 5.5 MT ha-1 at the vegetative stage and ≥ 9.7 MT ha-1 at the mature stage while Japanese and Siberian millet exhibit the lowest yields at ≤ 5.5 MT ha-1 at the vegetative stage and ≤ 6.3 MT ha-1 at the mature stage. Annual ryegrass was the most preferred grass (P ≤ 0.0057) with ≥ 60% removal at the vegetative stage and ≥ 40% removal at the mature stage. Siberian millet was the least preferred grass with ≤ 40% removal at the vegetative stage and ≤ 5% removal at the mature stage. While warm-season grasses meet the nutritional requirements of many classes of horses, Ca:P under 1:1 was observed as well as high NO3-N levels. These conditions could lead to limited mineral availability and possible nitrate toxicity. While teff and sudangrass have potential to be grazed by horses, Ca:P and NO3-N levels should be determined before grazing. Limited research is available regarding the role of leucine in regulating equine skeletal muscle protein synthesis. The objective of this study was to evaluate the effect of leucine on protein synthesis in cultured equine satellite cells by evaluating translation initiation factors in a western blot, the incorporation of puromycin using a nonradioactive surface sensing of translation (SUnSET) method, and measuring the incorporation of [3H]Phenylalanine (3HPhe) in a protein synthesis assay. Satellite cells from equine semimembranosus muscle were grown in cell culture until they developed into myotubes. Treatments used in the western blot consisted of a no leucine control (CON), leucine (LEU), control plus rapamycin (CR), and leucine plus rapamycin (LR). LEU exhibited higher 4E-BP1 and rpS6 phosphorylation when compared to CON with no change observed in mTOR phosphorylation. No increase in phosphorylation was observed in CR or LR treatments. Puromycin incorporation was measured on treatments including a no puromycin control, a no leucine control (CON), and a leucine treatment (LEU). These results showed a 1.6-fold increase in puromycin incorporation between CON and LEU (P = 0.0004). Treatments used in the protein synthesis assay consisted of a leucine titration ranging from 0-nm to 408-nm. These results showed muscle protein synthesis rates increased as a result of leucine treatments with significant differences observed at 204-nM and 408-nM leucine compared to the untreated cells. These treatments exhibited a 1.6-fold increase in protein synthesis rates when compared to the untreated control (P ≤ 0.02). This study demonstrated the phosphorylation of translation initiation factors downstream of mTOR as well as increased 3HPhe and puromycin with leucine treatment. These results suggest leucine can trigger muscle protein synthesis in horses through activation of the mTOR pathway.
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    Assessment of the Impacts of Various Grazing Management Strategies on Southern Minnesota Stream Channels
    (2018-05) Kim, Seongjun
    Stream riparian corridors are inherent to many farms in southern Minnesota. They are complex and diverse ecosystems, provide transportation for drainage from agricultural fields, and contribute to the quality of the larger watershed to which they belong. However, much of the 3.5 million miles of rivers in the United States are impacted, with sedimentation and excess nutrients being the most significant causes of degradation. The agricultural areas of southern Minnesota commonly use stream corridors as pasture since they are generally unsuitable for crops and provide a natural source of water for livestock. Traditional methods of grazing livestock can cause reduced vegetative cover, compacted soils, water contamination, sedimentation, and eroded banks. Managing livestock by limiting the location and duration of their grazing has seen some success in reducing the impact compared to conventional grazing methods. My research aims to further determine the impacts various grazing management strategies have had on streams. Geomorphic data from four sites across three streams are analyzed to evaluate effects of current grazing strategies and changes in grazing strategies. Grassed and wooded areas are also compared, as grazing directly influences the vegetative communities. The results suggest that both managed and grazing exclusion sites showed healthier channels than conventional grazing sites did, and that grassed bank areas contribute more to channel stability than wooded bank areas. In certain situations, managed grazing has the potential to be more beneficial to stream channel health than the prohibition of grazing.
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    Comparison Of Two Different Grazing Systems Incorporating Cool And Warm Season Forages For Organic Dairy Cattle
    (2017-01) Ruh, Kathryn
    Two pasture systems with enhanced in-field and landscape level species diversity were analyzed for yield, forage quality, and mineral characteristics across the grazing season at the West Central Outreach and Research Center organic dairy in Morris, MN from 2013 to 2015. System 1 was a diverse-mixture of cool season grasses and legumes. System 2 was the same combination of perennial grasses and included warm season annual grasses (BMR sorghum-sudangrass (Sorghum × drummondii; BMRSS) and teff (Eragrostis tef) grass). Organic dairy cows (n = 90) of Holstein and crossbred genetics were used to evaluate the effect of the two pasture systems on milk production, milk components (fat, protein, MUN, SCS), body weight, body condition score (BCS), and activity and rumination (min/d). The rumen fermentation of BMRSS, teff, cool season perennial pastures, and alfalfa were also studied using a dual flow continuous culture rumen fermentation system.
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    Evaluation of pasture biomass from cool-season pastures in the Midwestern USA with satellite imagery, compared to an electronic plate meter and herbage clippings.
    (2023-01) Dourado Clemente , Leticia
    Evaluation of pasture biomass measurements aids producers in knowing the availability of cool season grass in pasture for cattle grazing. The objective of this study was to compare satellite technology with the rising plate meter and forage biomass clippings as a method of pasture monitoring in the Upper Midwest of the USA. The study was conducted at the University of Minnesota West Central Research and Outreach Center, Morris, MN grazing dairy from May 2021 to October 2021 and May 2022 to September 2022. The pasture system was composed of cool-season perennials and included mixtures of meadow bromegrass (Bromus riparius Rehmann), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), orchardgrass (Dactylis glomerata L.), alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and white clover (T. repens L.), and intermediate wheatgrass (Thinopyrum intermedium). Grazing height and forage availability were measured weekly in 9 pastures with a Jenquip pasture plate meter (Jenquip, Feilding, New Zealand). Pastures ranged in size from 2.55 ha to 9.7 ha. Satellite images were from Planet Labs PBC (San Francisco, CA) and average normalized difference vegetation index (NDVI) values were calculated weekly for the area inside each pasture. Pearson correlations were from PROC CORR of SAS 9.4 and determined associations of forage biomass from the plate meter and satellite imagery. Across the summer grazing season, mean forage biomass was 3,267 kg DM/ha (range was 2,864 to 3,622 kg DM/ha) from the plate meter and 2,325 kg DM/ha (range was 985 to 3,321 kg DM/ha) from NDVI satellite images. The correlations for specific pastures of the rising plate meter and the satellite image NDVI ranged from 0.074 to 0.91 and the average correlation was 0.58. Correlations were greater with greater forage availability in the pastures. Alternative methods to calculate the biomass of pastures may provide more advantages for farmers to determine the grazing management of pastures.
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    The Revery Alone Won't Do: Fire, Grazing, and Other Drivers of Bee Communities in Remnant Tallgrass Prairie
    (2019-04) Pennarola, Nora
    The bee community in Minnesota’s tallgrass prairie is doubly threatened. The conversion of prairie to agriculture and development has fragmented the landscape nearly beyond recognition. Over vast swathes of the state, single species exist in monocultures where once highly diverse grasslands grew. On top of this, bees across the continent face pressures from parasites, pathogens, and pesticides. The pockets of remnant prairie that persist are dependent on human-mediated disturbance. Grazing and burning, which can be seen as analogues to historic disturbance patterns, are effective and important tools in maintaining prairie health. Through this thesis, I seek to parse out the differing impacts of these two management techniques on bee communities and to explore how environmental characteristics impact the suite of traits bees display in remnant prairies.