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 Retained interest in seedstock bulls: a transaction cost analysis(Montana State University - Bozeman, College of Agriculture, 2021) Kaiser, Rebecca Marie; Chairperson, Graduate Committee: Randal R. RuckerSeedstock cattle producers invest in bulls to introduce high quality genes into their cattle herds. Because the genetic traits bulls pass on to their calves are sometimes unobservable before breeding season, the quality of the bull at the time of the sale is uncertain. Some producers choose to sell bulls with retained semen interest, which grants them rights to the specified percentage of revenues from semen sales from the bull after it has been sold. This thesis examines the practice of retained semen interest in bulls and its effects on sale prices for the bull. After adapting the theory of auctions and share contracts and developing a theory of retained interest, I empirically test my hypotheses that 1) if there is more uncertainty regarding the attributes of the bull, the producer will be more likely to use a retained interest contract, and 2) a retained interest contract increases the value of a bull. I use a logit model to test the first hypothesis and hedonic price model, estimated using OLS, to test the second model. I find evidence to support both predictions, which supports my transaction cost model of contract choice. After controlling for quality, producers are more likely to retain interest in bulls that have greater variation in their quality. Also, bulls that are sold with retained interest earn significant premiums compared to bulls sold with lump sum prices. These results add to the transaction cost and share contract economic literature, as well as inform seedstock producers about the economic costs and benefits of retaining semen interest.Item Can targeted cattle grazing increase abundance of forbs or arthropods in sage-grouse brood-rearing habitat?(Montana State University - Bozeman, College of Agriculture, 2018) Payne, Jarrett MacKenzie; Chairperson, Graduate Committee: Jeffrey C. MosleySuboptimal brood-rearing habitat often limits greater sage-grouse (Centrocercus urophasianus) populations in western North America. In mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana [Rydb.] Beetle) brood-rearing habitat, dense sagebrush canopy cover (> 25% cover) may limit the understory forbs and arthropods that sage-grouse prefer to eat during summer. Targeted cattle grazing is a potential habitat management tool to reduce dense sagebrush. This study evaluated targeted cattle grazing on a landscape scale to increase forbs and arthropods within core sage-grouse brood-rearing habitat. Objectives of this study were to evaluate how well targeted cattle grazing reduced mountain big sagebrush canopy cover, increased forb abundance and diversity, and increased arthropod abundance. Targeted cattle grazing was applied within two large, contiguous pastures (625 ha each) in the Beaverhead Mountains of southwestern Montana. The two pastures were grazed simultaneously at a light stocking rate (6.25 ha/AUM) for two weeks each year in mid-October 2015 and 2016. Vegetation and arthropod responses were measured during the following June-early July (2016 and 2017, respectively) within 32 microsites where mountain big sagebrush canopy cover exceeded 30% pre-treatment. Microsites were 0.008 ha to match the spatial scale at which sage-grouse broods select fine-scale habitat. One of two treatments was randomly assigned to each microsite: a low moisture block protein supplement or no supplement (unsupplemented). In the first summer after treatment, supplemented microsites averaged 78% less sagebrush canopy cover (8% vs. 36%; P < 0.001) and 25% more forb canopy cover (15% vs 12%; P = 0.122). Sage-grouse forb canopy cover was 50% greater in supplemented microsites (3% vs. 2%; P = 0.003). Forbs also comprised a greater proportion of the herbaceous understory in the supplemented vs. unsupplemented sites (48% vs. 36%; P = 0.002). Arthropod abundances were greater in supplemented than unsupplemented microsites only during the wet year of 2017 when arthropods were 1.7-1.8x more abundant in supplemented microsites. Sagebrush canopy cover was reduced by cattle trampling, not browsing. My results demonstrate that targeted cattle grazing can increase abundance of forbs and arthropods in mesic, dense stands of mountain big sagebrush in sage-grouse brood-rearing habitat.Item The nutritive value of mixed prairie : sagebrush-bunchgrass and forest-alpine ranges for grazing cattle(Montana State University - Bozeman, 1978) Strazdas, Petras; Chairperson, Graduate Committee: J. E. (John Edgar) TaylorItem Economic determinants of the variation in average carcass weight for United States slaughter cattle(Montana State University - Bozeman, College of Agriculture, 2016) Vogstad, Amanda Rae; Chairperson, Graduate Committee: Randal R. RuckerOver the past century, average carcass weights of slaughter cattle have demonstrated a substantial upward trend, as well as year-to-year volatility. Since the mid-1970s however, increasing average carcass weights have coincided with high levels of beef production but with diminishing beef cow herds. Increased beef production with fewer cow numbers is likely explained by technological advancements throughout the beef industry. Annual variability in average carcass weight, on the other hand, is hypothesized to arise because of the dynamics of fed cattle production arising from changes in input and output prices. To identify the economic factors responsible for the variation in average carcass weight theoretical and empirical models are developed. Based on the theoretical model, cattle feeders choose the levels of corn and labor that yield optimal carcass weights by equating each factor's value marginal product to the marginal cost. Theoretical predictions are then tested using 85 years of aggregate annual data in a distributed lag model. Overall, we find coefficient estimates on the input and output prices consistent in sign with our theoretical predictions. Of importance is the finding that the manufacturing wage accounts for an estimated 61 percent of the total input and output price induced variation in average carcass weight. A trend for technological change in the beef industry accounts for a yearly increase in average carcass weight of 3.6 pounds.Item The in vitro digestibility and utilization of Big Sagebrush and Black Sagebrush(Montana State University - Bozeman, College of Agriculture, 1985) Striby, Karl DavidItem Dispersal by enzymatic digestion and recovery of bovine oocytes from whole ovaries(Montana State University - Bozeman, College of Agriculture, 1976) Strickland, James DaileyItem Frequency of calving in PGF 2alpha estrous synchronized cattle(Montana State University - Bozeman, College of Education, Health & Human Development, 1985) Kautz, Robert JayItem Isolation and partial characterization of macrophages from bovine peripheral blood(Montana State University - Bozeman, College of Agriculture, 1990) Mukherjee, GoutamItem Utilization of biuret and urea as affected by feeding interval and energy level(Montana State University - Bozeman, College of Agriculture, 1970) Armitage, Jesse George