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 Influence of genotype on in vitro dry matter disappearance rate, estimated microbial yield and in vivo digestive physiology of barley(Montana State University - Bozeman, College of Agriculture, 1991) Kemalyan, Ruth EllenItem Effects of alfalfa variety and nitrogen status on pasture bloat in ruminants(Montana State University - Bozeman, College of Agriculture, 2001) MacDonald, Charles DonaldItem Influence of amino acids and branch chain organic acids on ruminant fiber fermentation(Montana State University - Bozeman, College of Agriculture, 1986) Clark, Connie KayItem Effects of increasing tetany risk ratio and magnesium supplementation on mineral balance and feeding behavior by ruminants(Montana State University - Bozeman, College of Agriculture, 2011) Norvell, Tess Marie; Chairperson, Graduate Committee: John Paterson.Three experiments were conducted to evaluate the effects of increasing the tetany risk ratio on blood serum Mg levels, nutrient digestion, mineral balance, and Mg supplementation source and feeding behavior. Experiments 1 and 2 were randomized complete block designs, with 24 wethers were maintained in individual metabolism crates and assigned to four treatments (6 wethers/treatment). Experiment 1 compared tetany risk ratios (TRR) of 1.6, 2.3, 2.9, or 3.5. Dry matter, NDF, and N digestibilities were not different between treatments. Nitrogen retention decreased (P < 0.05) as the tetany risk ratio increased. No treatment differences were recorded in Mg, Ca, K, or P balance. The TRR 2.3 treatment had the greatest decrease (P < 0.05) in serum Mg after 15d. Experiment 2 compared tetany risk ratios of 1.5, 2.6, 1.5 plus MgO, or 1.5 plus MgCl. The TRR 2.6 treatment showed increased (P < 0.05) DM, NDF, and N digestibilities when compared to all other treatments. Nitrogen digestibility decreased (P < 0.05) with the addition of supplemental Mg. No treatment differences in Mg, Ca, K, or P balance were recorded. The TRR 2.6 treatment had the greatest decrease (P < 0.05) in serum Mg after 5 d. Experiment 3 was a cafeteria study using a switchback design, 23 Angus heifers were weighed and randomly assigned to one of two locations (11 heifers in drylot, and 12 heifers on pasture) containing two mineral supplements (0.0% Mg and 10.0% Mg). The groups were rotated between locations after 15 d for 30 d of measurements. Individual mineral consumption (grams/d), feeder attendance (trips/d), and feeding duration (seconds/d) were measured using a GrowSafe® individual feeding system. Heifers consumed 119% more (P < 0.01) 0.0% Mg supplement each day than the 10.0% Mg. Heifers made almost twice as many (P < 0.01) trips to the feeder, and spent an additional 91.3 s consuming the 0.0% Mg than the 10.0% Mg. Total mineral intakes were 87.3 % greater (P < 0.01) when supplemented on pasture compared to drylot. During the first 15 d, total mineral intakes were higher (P < 0.01) than for the second 15 d.