Theses and Dissertations at Montana State University (MSU)
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Item Identification and cultivation of methyllycaconitine degraders from wild ruminants to protect against larkspur poisoning in range cattle(Montana State University - Bozeman, College of Agriculture, 2021) Grace, Savannah Gray; Chairperson, Graduate Committee: Carl Yeoman and Craig Carr (co-chair); Joanna-Lynn C. Borgogna, Craig A. Carr, Lance B. McNew, Brian Bothner and Carl J. Yeoman were co-authors of the article, 'Degradation of toxic alklaoids in Delphinium occidentale species occurs within the gastrointestinal tract of Montana's wild ruminants' submitted to the journal 'American Society of Animal Science' which is contained within this thesis.; Joanna-Lynn C. Borgogna, Mostafa Elshahed, Lance B. McNew, Brian Bothner, Craig A. Carr and Carl J. Yeoman were co-authors of the article, 'Degradation of the toxic alkaloid, methyllycaconitine by wild ruminant species is predominantly mediated by rumen fungi' submitted to the journal 'American Society of Animal Science' which is contained within this thesis.Tall larkspur (Delphinium spp.) in the western United States present a serious toxicity danger to rangeland cattle. Consumption of Methyllycaconitine (MLA), the toxic alkaloid in larkspur plants, can cause annual losses of 5-15% of range cattle in grazing pastures with sufficient larkspur. With the wide distribution and abundance of larkspur, wild ruminants in Montana likely encounter tall larkspur while foraging; however, no evidence suggests they are negatively affected by MLA's toxic effects. Therefore, we evaluated: i) whether alkaloids in Delphinium spp., and MLA specifically degraded within ruminal specimens collected from Montana's wild ruminant species over 48 h using in vitro incubations; ii) whether observed degradative activities were abiotic, or mediated by either the fungal or non-fungal (mostly bacterial) residents of the ruminal microbiota in wild ruminant specimens; and iii) if representative microbial isolates individually possessed the ability to degrade MLA within in vitro incubations. Rumen samples were collected from wild ruminant species during the 2019 and 2020 hunting seasons using legal methods by volunteer hunters. In all assays, total alkaloid was measured spectrophotometrically, and MLA by High-Performance Liquid Chromatography Mass Spectrometry (HPLC) from initial and final incubations. Our results demonstrated that, with the exception of white-tailed deer, all wild ruminant species exhibited variable degradative abilities in both total alkaloid (P< 0.001) and MLA (P< 0.001) assays and that such degradation was predominantly mediated by ruminal fungi. Additionally, screening of 15 fungal isolates, representing 10 known genera and 2 isolates of unknown taxonomic identity each obtained from herbivorous hosts, determined all were capable of degrading MLA to some extent. Fungal isolates obtained from wild ruminants exhibited greater degradative activity, with Aestipasuomyces R5 isolated from wild sheep degrading 71% of MLA (P<0.001). Overall, our results indicate that degradation of both total alkaloid and MLA-specifically occurs within the gastrointestinal tract of Montana's wild ruminants and that it is largely influenced by fungal activity. Additionally, fungal strains isolated from wild ruminants are capable of degrading MLA and have the potential to be further used as a direct fed microbial to rangeland cattle as an optimal way to mitigate larkspur toxicosis.Item Effects of grazing after wildfire on soil health in eastern Montana(Montana State University - Bozeman, College of Agriculture, 2021) Hanson, Joshua Todd; Chairperson, Graduate Committee: Clayton B. Marlow; Clayton B. Marlow, Kurt O. Reinhart, Lance T. Vermeire and Sam A. Wyffels were co-authors of the article, 'Effects of grazing after wildfire on indicators of soil health in eastern Montana' submitted to the journal 'Fire ecology' which is contained within this thesis.Rangelands are resilient to grazing and fire. However, the resilience of rangelands may be degraded by livestock grazing too soon after wildfire. Due to the growing interest in soil health and its link to sustainable grazing, following a large wildfire (109,346 ha, Lodgepole complex in 2017) we tested the effect of grazing (grazed verses no grazing) on three indicators of soil health in ponderosa pine savvanas of the northern Great Plains. We measured indicators of soil hydrologic function (i.e., soil hydraulic conductivity), properties related to nutrient cycling (i.e., soil organic matter, plant available nutrients, pH), and soil structure (i.e., aggregate stability) in 2019 and 2020. Grazing occurred two out of three years following the fire. Most indicators of soil health were not appreciably affected by grazing post-fire. However, we detected a marginally significant negative effect of grazing on soil organic matter. Specifically, soil organic matter was 7% greater in ungrazed than grazed areas. No other grazing treatment effects were detected. Several soil health metrics varied between sampling years. Our results suggest that grazing(two out of the three years) following fire is unlikely to negatively affect many indicators of soil health of ponderosa pine savannas in the northern Great Plains. The increased organic matter observed by resting did not have an appreciable impact on the other soil health metrics. These findings suggest that soil health indicators are relatively resilient to grazing after wildfire and have implications for grazing policy post-fire.Item Native pollinators: the effects of livestock grazing on Montana rangelands(Montana State University - Bozeman, College of Agriculture, 2019) Blanchette, Gabrielle Elizabeth; Chairperson, Graduate Committee: Craig Carr; Michael A. Ivie (co-chair)Although native pollinators on rangelands serve, in part, as food at higher trophic levels, their primary ecosystem function is pollination. With 70% of western U.S. rangelands grazed by livestock, understanding how grazing affects native pollinators is a key component to managing rangelands, yet it is not well understood. In this study, I investigated how cattle grazing influences both diversity and abundance of native pollinators, including bees and wasps, syrphid flies, butterflies, and moths at two research locations for six to 10 weeks during the spring of 2016, 2017, and 2018. The first site, near Sidney, MT, served to understand if pollinators were more closely associated with active cattle grazing or rested pastures. The second site, near Roundup, MT, served to understand if pollinators were more associated with pastures either enrolled or not enrolled in the Sage Grouse Initiative, or pastures that had not experienced livestock grazing in previous seven years. Colored pan traps were deployed weekly in each treatment at each site. In addition to pollinator collections, weekly measurements of vegetation via Daubenmire frame were also collected. I collected 17,078 specimens at Sidney and 13,683 specimens at Roundup. My results suggest that in drier sagebrush landscapes, native pollinators are positively to neutrally associated with pastures moderately grazed by livestock. However, in mixed grass prairie landscapes that receive high precipitation, rest-rotational grazing does not appear to have a significant effect on primary native pollinators.Item Effects of rangeland fertilization on forage crop yield and quality(Montana State University - Bozeman, 1978) Nemeth, Chris EdwardItem Range ecology and relations of mule deer, elk, and cattle in the Missouri River Breaks, Montana(Montana State University - Bozeman, College of Letters & Science, 1965) Mackie, Richard J.Item A comparison of three range measurement techniques and a study of the response of native vegetation to protection from sheep grazing(Montana State University - Bozeman, College of Agriculture, 1960) Vogel, W. G.Item Pronghorn range use and relation to livestock in southeastern Montana(Montana State University - Bozeman, College of Letters & Science, 1971) Freeman, James SamuelItem A comparison of Range Condition Analysis and Ecodata to evaluate seral stages(Montana State University - Bozeman, College of Agriculture, 1995) Winslow, Susan RaeItem Evaluation of sweep sampling as a method for determining grasshopper community composition on rangeland(Montana State University - Bozeman, College of Agriculture, 1996) Larson, Deanne PassaroItem Effect of summer fallowing, perennial crop cover and conservation reserve practices on soil nitrate distribution(Montana State University - Bozeman, College of Agriculture, 1994) Pannebakker, Lynn S.; Chairperson, Graduate Committee: Jim BauderDryland agriculture is an economically feasible method of producing crops in some parts of the semi-arid regions of the mid-west and western United States. Summer fallowing, which is commonly practiced in these regions, serves to replenish soil moisture and plant-available nitrate-nitrogen (N0 3--N), while also stabilizing production and more uniformly distributing the work load. In areas where dryland agriculture is concentrated, summer fallowing may lead to N0 3--N contamination of ground-water due to lack of plant uptake of excess water and N. Under certain conditions of precipitation, soil percolation, slope, and cropping intensity, summer fallowing has been shown to cause elevated N03--N concentrations in shallow groundwater wells. These elevated N0 3--N levels have been detected in several areas of the U.S. Two areas where high N0 3--N concentrations have been repeatedly found in groundwater samples are in northeastern and central Montana. Judith Basin and Fergus Counties of Montana were selected for soil sampling to assess any differences in soil NO3--N concentrations under three different land use systems: 1) crop fallow rotation, 2) acreage enrolled in the USDA Agricultural Stabilization and Conservation Service (ASCS) conservation reserve program (CRP), 3) and rangeland. Soil samples were collected to a depth of three m (10 ft) at four different sites in each county. Soil samples from all sampling depths at each of the eight sites were analyzed for gravel percent (>2 mm diameter) , N0 3--N load, and N0 3--N concentration. Samples from 0 m to 0.6 m were also analyzed for total-N concentration. Trends in soil N0 3-N give evidence that summer fallowing may be the cause of N0 3--N in shallow groundwater in some areas Of Montana where dryland cropping is practiced. Overall, average soil N0 3--N concentration throughout the sampled soil profile was 4.2, 2.0, and 1.3 mgkg-1 for the crop fallow, CRP, and rangeland land use practices, respectively. Average N0 3--N concentration in Fergus County ranged from 2.5 mgkg-1 to 20.4 mgkg-1 under crop fallow while it ranged from only 0.9 to 6.2 mgkg-1 and from 0.9 to 4.2 mgkg-1 for the CRP and rangeland uses, respectively. Average N0 3--N concentration in Judith Basin County ranged from 1.4 mgkg-1 to 6.9 mgkg-1, 0.6 mgkg-1 to 2.0 mgkg-1, and from 0.8 mgkg-1 to 1.4 mgkg-1 under crop fallow, CRP, and rangeland land use systems, respectively. Assuming that extensive use of crop fallow causes increased N0 3--N concentrations under some conditions, alternative land use management practices may be effective in reducing N0 3--N levels in such areas.