Understanding and Mitigating the Adverse Effects of Poisonous Plants on Livestock Production Systems

Goals / Objectives
Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2.

Project Methods
The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers.

Progress 10/01/23 to 09/30/24

Outputs
PROGRESS REPORT Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. This is the final report for this project (2080-32630-014-000D), ⿿Understanding and Mitigating the Adverse Effects of Poisonous Plants on Livestock Production Systems⿝, which has been replaced by new project 2080-21500-001-000D, ⿿Developing Mitigation Strategies for Poisonous Plants in Livestock Production Systems⿝. For additional information, please see the new project report. Progress was made on all five objectives and their sub-objectives, all of which fall under National Program 215, Component I, Improved Rangeland Management for Enhanced Livestock Production, Conservation and Ecological Services. Progress on this project focuses on Problem A, the need for developing economic livestock grazing systems for rangelands that meet global food security objectives while being adaptable to changing climate and varying environmental conditions and preserve the natural resources integrity. Results have been communicated through peer-reviewed publications and to stakeholders through various means. In support of Objective 1, various herbicides were tested to determine their efficacy in aiding the establishment of newly seeded grass species in rangelands infested with annual grasses and containing populations of poisonous plants. Herbicides were evaluated to control Plains larkspur (Delphinium geyeri) at two locations: Cheyenne, Wyoming, and Livermore, Colorado. Plots were established and treated with herbicides during the summer of 2021 in Cheyenne and the summer of 2022 in Livermore. Evaluations of control effectiveness were conducted one- and two-years post-treatment. Herbicide applications were timed to target different stages of plant growth (early vegetative and flowering stages). Plots in Livermore, Colorado, were evaluated two years after treatment in the summer of 2024. Under Objective 2, a comprehensive approach was used to evaluate toxin accumulation in various plant species to understand the risks posed to livestock. Alkaloid profiles of several Delphinium species were investigated. Delphinium species were collected over the growing seasons of 2020, 2021, and 2022 at nine different locations to investigate how alkaloid concentrations fluctuate over time and across locations. For Objective 3, animal studies focusing on six pyrrolizidine alkaloids in a P53 knockout mouse model were conducted. Detailed examinations for cancer-type lesions were performed in P53 knockout mice exposed to riddelliine. Approximately 40% of the mice exhibited hepatic and other tissue neoplastic diseases. Earwax samples collected from pregnant cows grazing pastures containing teratogenic lupine plants were analyzed for teratogenic alkaloids. The study found no correlation between teratogenic alkaloid concentrations in earwax samples and the occurrence of malformed calves. Studies were conducted to assess serum mannosidase activity and sensitivity to the toxin swainsonine in different animal species, including horses, cows, goats, and sheep. The research demonstrated correlations between in vitro inhibition of serum mannosidase by swainsonine and in vivo swainsonine toxicosis. The major diterpene acids in broom snakeweed and common metabolites found in serum of animals fed broom snakeweed were identified. Additionally, the chemotypes in two broom snakeweed species were defined based on diterpene acid profiles, and structural identities of isolated diterpene acids were determined. Noninvasive sampling techniques were used to detect larkspur alkaloids in earwax, hair, oral fluid, and nasal mucus in cattle that were administered single doses of Delphinium barbeyi and Delphinium ramosum. Lupine alkaloids were detected in the earwax, hair, oral fluid, and nasal mucus in cattle that were administered a single dose of Lupinus leucophyllus. In support of Objective 4, an experiment was conducted to determine if cattle would decrease their consumption of a basal diet following intoxication from larkspur (Delphinium spp.). The results of this study suggest alterations in basal diet intake by cattle following larkspur toxicosis. Common veterinary drugs were evaluated as potential therapeutic treatments for animals poisoned by several plants. Studies demonstrated the efficacy of a drug already on the market for treating hemlock toxin coniine and tree tobacco toxin anabasine in a mouse model. Research explored the effects of cattle intoxication from larkspur on basal diet consumption and subsequent weight gain. Studies identified four toxic diterpenoid hepatotoxins in the plant Salvia reflexa and confirmed their toxicities in goats, mice, and cattle, and resulted in publications detailed poisoning incidents and comparative pathology in various animal species. The effects of low-dose selenium intake in cattle and sheep were characterized, with ongoing analyses of mineral, biochemical, and histological samples. Studies demonstrated that feeding high selenium-containing forage to sheep caused disruptions in spermatogenesis, leading to decreased sperm motility and increased morphological abnormalities. Similar trials in cattle showed minimal negative impacts on sperm quality but observed clinical signs of chronic selenium poisoning. Histological examinations of testicular lesions are underway, correlating with chemical analyses. For Objective 5, ARS researchers demonstrated that larkspur toxicity in cattle is both age and sex dependent. Cattle were characterized as larkspur susceptible or resistant, and subsequent studies evaluated their offspring's susceptibility. After evaluating the past 15 years of research, the hypothesis that larkspur susceptibility in Angus cattle is a heritable trait has been rejected. Efforts have been redirected towards using a mineral mix to reduce the impact of larkspur on cattle which has been shown to have significant effects in laboratory studies. Studies have compared pen-raised sheep with sheep raised on death camas-infested rangelands to assess differences in consumption and susceptibility to adverse effects. Pen raised sheep were grazed on death camas (Zigadenus paniculatus) infested rangelands in the spring of 2021 and the spring of 2022 to determine if animal factors such as hungry or satiated animals will cause animals to differ in their preference to consume death camas. Sheep that were raised grazing native rangelands were grazed in 2023. Sheep were grazed in Utah in 2021 and Idaho in 2022 and 2023. Sheep were grazed when the plant was in the early vegetative stage of plant growth and again when the plant was in the flower stage to determine if animals had a preference for phenological growth stage. Grazing occurred at different growth stages of the plant, and samples are undergoing analysis for nutritional content. Artificial Intelligence (AI)/Machine Learning (ML) Neither artificial intelligence (AI) or machine learning (ML) methods were used for this project during FY 2024. ACCOMPLISHMENTS 01 Larkspur toxicosis alters basal diet intake by cattle. ARS researchers in Logan, Utah, conducted a study to examine the effects of larkspur consumption on cattle. Understanding the impact of larkspur on cattle diet intake helps to devise better management strategies to mitigate the risks associated with larkspur poisoning. This study measured how much and how long larkspur ingestion leads to a reduction in basal diet intake. If cattle have a reduced diet intake, they are not gaining weight which reduces profitability. As the amount of larkspur consumed increased, the reduction in intake of their regular diet became more pronounced, and this reduction persisted for two days post-dosing, indicating that the immediate effects of larkspur on dietary intake are substantial. The dose-dependent reduction in diet intake suggests that even small amounts of larkspur can adversely affect cattle feeding behavior. The two to three-day recovery period highlights the need for careful monitoring of cattle after they have grazed in areas with larkspur. 02 Identification of two death camas chemotypes within a population and evaluation of toxicity. Foothill death camas is a native perennial forb found extensively throughout the western United States which is notorious for its toxicity, primarily due to the presence of various alkaloids. ARS researchers in Logan, Utah, have discovered a population of death camas exhibiting two distinct chemical profiles, referred to as chemotypes, within the same location. The study involved sampling the population of foothill death camas and determining the percentage representation of each chemotype, and acute toxicity tests were conducted using mice and sheep to compare the toxic effects of the two chemotypes. Chemotype 1 also had higher toxicity levels than chemotype 2 which indicate significant variation in the chemical profiles and toxicities of foothill death camas within a single population. This study underscores the importance of recognizing chemical variability within plant populations, particularly those with toxic properties such as foothill death camas. The variation in alkaloid profiles and their differential toxicity in different animal models suggest that caution is necessary when managing grazing practices in areas where death camas is present. 03 Silencing of the transmembrane transporter (swnT) gene of the fungus Slafractonia leguminicola results in a reduction of mycotoxin transport. ARS researchers in Logan, Utah, in collaboration with New Mexico State University, conducted a detailed investigation into the role of a putative trans-membrane transporter, swnT, in the transport of mycotoxins produced by the plant pathogen Slafractonia leguminicola, which infects red clover and other legumes, causing black-patch disease. RNA interference (RNAi) technology to silence the swnT gene, and the effectiveness of the silencing, was then evaluated by measuring the transcript levels of swnT and the consequent changes in mycotoxin concentrations. Silencing of swnT led to a marked decline in the active efflux of mycotoxins from the mycelia into the media. This was evidenced by higher concentrations of mycotoxins retained within the mycelia, as opposed to being secreted into the surrounding environment. The study's findings have significant implications for understanding the pathogenic mechanisms of Slafractonia leguminicola. By elucidating the role of the swnT transporter in mycotoxin secretion, researchers can better understand how this fungus causes black-patch disease in legumes. The ability to disrupt mycotoxin transport through gene silencing offers potential strategies for controlling the spread and impact of this disease. 04 Impact of selenium biofortification on production characteristics of forages grown following standard management practices in Oregon. Selenium (Se) is an essential micronutrient for many animals and humans, and its concentration in forage can significantly impact livestock health. ARS scientists in Logan, Utah, in collaboration with researchers at Oregon State University, have shown that the application of selenate increases forage Se concentration regardless of the fertilization practices employed, and indicates the effectiveness of selenate in enhancing the Se content of forage. The application of selenate amendments is an effective strategy to enhance forage Se concentrations, which is essential for maintaining livestock health. However, the interaction between Se and sulfur fertilization, along with other factors such as soil characteristics and weather conditions, necessitates a careful and adaptive management approach. By combining targeted selenate and fertilization practices, optimal forage growth and quality can be achieved, ensuring the nutritional needs of grazing livestock are met. Further research is needed to understand the long- term effects of selenate and sulfur amendments on soil health and forage quality.

Impacts
(N/A)

Publications

Progress 10/01/22 to 09/30/23

Outputs
PROGRESS REPORT Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. This report documents progress for project 2080-3263-014-000D, titled, ⿿Protection of Food and Water Supplies from Pathogens and Human Induced Chemicals of Emerging Concern⿝. In support of Objective 1, ARS researchers at Logan, Utah, evaluated the ability of various herbicides to control larkspur (Delphinium species) at two different locations. Plots were established and sprayed with herbicides at one location during the summer of 2021. Those plots were evaluated for control, 1 year after treatment, during the summer of 2022 and 2 years after treatment the summer of 2023. Plots were established and sprayed with herbicides at a second location during the summer of 2022. Plots were evaluated for control, 1 year after treatment, during the summer of 2023. The herbicides were applied at two different times of plant growth. First application was during the early vegetative growth stage and the second application was when plants were in the flowering stage. In support of Objective 2, ARS researchers at Logan, Utah, collected two Delphinium species over the growing season to determine how alkaloid concentrations change over the growing season and between years and how they might vary at different locations. Samples have been analyzed for alkaloid concentration and data presented at the 76th Annual Society of Range Management meeting in Boise, Idaho. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. ARS scientists at Logan, Utah, also continue research to characterize the alkaloid profiles from several Delphinium species that had not been investigated previously. Methyllycaconitine, the larkspur toxin most commonly associated with poisoning of cattle was detected in most species. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. Under Sub-objective 2.2, ARS scientists at Logan, Utah, surveyed several Astragalus species for swainsonine and selenium and are preparing a publication. Under Sub-objective 2.4, ARS scientists at Logan, Utah, have completed the macro and micro-nutrient analyses of the plants and are preparing a publication. Under Sub-objective 2.7, ARS scientists at Logan, Utah, have collected specimens from various herbarium collections representing several taxa of interest. Chemical analysis has been completed for most of the samples. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. In support of Objective 3, ARS researchers at Logan, Utah, have completed animal work studying six pyrrolizidine alkaloids in a P53 knockout mouse model. Additional groups will be completed this summer. The microscopic studies and statistical analyses are mostly completed. This work has already resulted in several peer-reviewed publications and presentations. A recent presentation entitled ⿿Comparison of Acute Dehydropyrrolizidine Alkaloid Toxicosis in C57BL6/J Mice Gavaged with Riddelliine, Riddelliine N-oxide, Senecionine, Senecionine N-oxide, Seneciphylline, Lasiocarpine and Heliotrine⿝ was awarded best graduate student present at the 2022 ACVP meeting. Two more manuscripts describing this work have been submitted for publication. In support of Objective 4, ARS researchers at Logan, Utah, are actively evaluating various drugs as potential therapeutic treatments for animals poisoned by several plants. Some recent work has shown that a drug which is already on the market can be used as a drug treatment for the hemlock toxin coniine in a mouse model. Additional studies will be performed in a goat model this summer. Additionally, ARS researchers at Logan, Utah, studied the effect of cattle intoxication from larkspur (Delphinium spp.) on their consumption of a basal diet and subsequent weight gain. A manuscript describing these results has been submitted for publication in a peer-reviewed journal. Under Sub-objective 4.2, ARS researchers at Logan, Utah, identified four toxic diterpenoid hepatotoxins in the plant Salvia reflexa. The toxicities of these compounds were confirmed in goats, mice, and cattle. This research has been detailed in four book chapters and two peer-reviewed publications. Additionally, two large poisoning incidents of more than 300 animals were recently identified and determined to be caused by Salvia reflexa. A publication detailing the findings in those cases, in addition to another describing the comparative pathology of S. reflexa in mice, goats and cattle have been prepared, and are currently under review. In support of objective 5, ARS researchers at Logan, Utah, compared pen raised sheep versus sheep that were raised on death camas (Zigadenus paniculatus) infested rangelands to determine if there is a difference in how much death camas they will eat and if there is a difference in their susceptibility to the adverse effects of death camas. Sheep were grazed when the plant was in the early vegetative stage of plant growth and again when the plant was in the flower stage to determine if animals had a difference in preference depending upon the phenological growth stage. Samples are currently being processed and analyzed for nutrition content and data is being prepared for statistical analysis. ACCOMPLISHMENTS 01 Endophyte produced bioactive secondary metabolites in Ipomoea species. Understanding host symbiont relationships and the bioactive metabolites produced is critical to our basic understanding of these relationships and required to better predict risk and make recommendations to reduce livestock losses. ARS researchers in Logan, Utah, in collaboration with other researchers surveyed several Ipomoea taxa for endophyte produced bioactive metabolites in Ipomoea species that are responsible for various poisonings of animals. The research has impact as it provides basic information but also provides information to extension agents and range scientists at the various government agencies, as well as livestock producers, and other investigators studying toxic plants and natural products. 02 Slaframine and swainsonine transport and biosynthesis in Slafractonia legumnicola. Slaframine and swainsonine are two mycotoxins produced by the pathogen Slafractonia leguminicola. ARS Researchers in Logan, Utah, in collaboration with scientists at New Mexico State University, investigated the role of a transmembrane reporter in the transport of two mycotoxins, swainsonine and slaframine. The research has impact as it provides basic information to other scientific researchers about the transport of swainsonine and slaframine and the role of this transporter in pathogenesis. Understanding these mechanisms may provide information to disrupt the pathogen and subsequent poisoning of livestock. 03 Selenium application methodologies and rates determined for forages. Application of selenate to forages is effective at increasing forage selenium concentrations and thus alleviating selenium deficiencies in livestock. Little is known of methods and high application rates of selenium that can be applied to forages to obtain desired and safely elevated selenium concentrations for grazing livestock. ARS researchers at Logan, Utah, and scientists at Oregon State University have determined effective ways to apply selenate amendments to produce safe selenium-biofortified forages that producers can use with targeted grazing strategies to produce healthier livestock in selenium deficient areas.

Impacts
(N/A)

Publications

Stegelmeier, B.L., Davis, Z.T. 2023. Poisonous plants. In: Haschek-Hock, W. M., Rousseaux, C.G., Wallig, M.A., Bolon, B., editors. Haschek and Rousseaux's Handbook of Toxicologic Pathology: Environmental toxicologic pathology and selected toxicant classes. 4th Edition, Volume 3. San Diego, CA: Academic Press. p. 489-546.
Green, B.T., Welch, K.D., Lee, S.T., Stonecipher, C.A., Gardner, D.R., Stegelmeier, B.L., Davis, T.Z., Cook, D. 2023. Biomarkers and their potential for detecting livestock plant poisonings in western North America. Frontiers in Veterinary Science. 10. Article 1104702. https://doi. org/10.3389/fvets.2023.1104702.
Ubiali, D.G., Lee, S.T., Gardner, D.R., Cook, D., Pereira, G.O., Riet- Correa, F. 2022. Cestrum axillare (Solanaceae) poisoning in ruminants. Toxicon. 218:76-82. https://doi.org/10.1016/j.toxicon.2022.09.005.
Hueza, I.M., Dipe, V.V., Gotardo, A.T., Gardner, D.R., Almeida, E., Gorniak, S.L. 2023. Potential immunomodulatory response associated with L- mimosine in male Wistar rats. Toxicon. 226. Article 107084. https://doi. org/10.1016/j.toxicon.2023.107084.
Das, S., Gardner, D.R., Neyaz, M., Charleston III, A.B., Cook, D., Creamer, R. 2023. Silencing of the transmembrane transporter (swnT) gene of the fungus Slafractonia leguminicola results in a reduction of mycotoxin transport. Fungi. 9(3). Article 370. https://doi.org/10.3390/jof9030370.
Hall, J.A., Bobe, G., Filley, S.J., Bohle, M.G., Pirelli, G., Wang, G., Davis, T.Z., Banuelos, G.S. 2023. Impact of selenium biofortification on production characteristics of forages grown following standard management practices in Oregon. Frontiers in Plant Science. 14. Article 1121605. https://doi.org/10.3389/fpls.2023.1121605.
Hall, J.A., Bobe, G., Filley, S.J., Pirelli, G.J., Bohle, M.G., Wang, G., Davis, T.Z., Banuelos, G.S. 2023. Effects of amount and chemical form of selenium amendments on forage selenium concentrations and species profiles. Biological Trace Element Research. 201:4951-4960. https://doi.org/10.1007/ s12011-022-03541-8.
Zabaleta, G., Lee, S.T., Cook, D., Aguilar, M., Iannone, L.J., Robles, C., Martinez, A. 2022. Indole-diterpenes alkaloid profiles of native grasses involved in tremorgenic syndromes in the Argentine Patagonia. Toxicon. 217:107-111. https://doi.org/10.1016/j.toxicon.2022.08.001.
Paim, R.C., de Paula, L., Soares, D.S., Rocha, T.G., Ribeiro, A.L., Barros, N., dos Santos, F.C., Ferreira, H.D., Gomes-Klein, V.L., Soto-Blanco, B., de Oliveira-Filho, J.P., da Cunha, P., Riet-Correa, F., Pfister, J., Cook, D., Fioravanti, M., Botelho, A. 2023. Toxic plants from the perspective of a "Quilombola" community in the Cerrado region of Brazil. Toxicon. 224. Article 107028. https://doi.org/10.1016/j.toxicon.2023.107028.
Quach, Q.N., Clay, K., Lee, S.T., Gardner, D.R., Cook, D. 2023. Phylogenetic patterns of bioactive secondary metabolites produced by fungal endosymbionts in morning glories (Ipomoeaee, Convolvulaceae). New Phytologist. 238(4):1351-1361. https://doi.org/10.1111/nph.18785.
Pistan, M.E., Gutierrez, S.A., Schnittger, L., Gardner, D.R., Cholich, L.A. , Gonzalez, A.M. 2022. Localization of the fungal symbiont (Chaetothyriales) in Ipomoea carnea. Botany. 100(9):729-736. https://doi. org/10.1139/cjb-2022-0033.
Kono, I.S., Faccin, T.C., de Lemos, G.A., Di Santis, G.W., Bacha, F.B., Guerreiro, Y.A., de Oliveira Gaspar, A., Lee, S.T., de Castro Guizelini, C. , Leal, C.B., de Lemos, R.A.A. 2022. Outbreaks of Brachiaria ruziziensis and Brachiaria brizantha intoxications in Brazilian experienced cattle. Toxicon. 219. Article 106931. https://doi.org/10.1016/j.toxicon.2022. 106931.
Schardl, C.L., Afkhami, M.E., Gundel, P.E., Iannone, L.J., Young, C.A., Creamer, R., Cook, D., Berry, D. 2022. Diversity of seed endophytes: Causes and implications. In: Scott, B., Mesarich, C., editors. The Mycota: Plant relationships. 3rd Edition, Volume 5. Cham, CH: Springer Cham. p. 83- 132. https://doi.org/10.1007/978-3-031-16503-0_5.

Progress 10/01/21 to 09/30/22

Outputs
PROGRESS REPORT Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. In support of Objective 1, ARS researchers at Logan, Utah, grazed sheep on death camas (Zigadenus paniculatus) infested rangelands to determine if a state of hunger will increase an animal⿿s preference to consume death camas. Sheep were grazed at two locations in Utah in 2019 and 2021 as well as one location in Idaho in 2022. Sheep were grazed when the plant was in the early vegetative stage of plant growth and again when the plant was in the flower stage, to determine if the phenological growth stage of death camas affects a sheep⿿s preference to consume the plant. Under Sub-objective 1.2, ARS researchers at Logan, Utah, evaluated several herbicides for control of plains larkspur (Delphinium geyeri) at a location in Wyoming and another in Colorado to determine if newly developed herbicides can control plains larkspur. Plots were sprayed with herbicides in Wyoming during the summer of 2021. Those plots were evaluated for control during the summer of 2022. Plots in Colorado were sprayed with herbicides during the summer of 2022. The herbicides were applied at two different times of plant growth. First application was during the early vegetative growth stage and the second application was when plants were in the flowering stage. The results suggest that several herbicides can provide good control of plains larkspur. Under Sub- objective 1.3, ARS researchers at Logan, Utah, conducted experiments in a greenhouse which demonstrated that an iron soil amendment (zero valent iron) will inhibit selenium uptake into selenium-accumulating forages grown in soils containing high amounts of selenium. This soil amendment was also found to increase forage mass of non-accumulator forages in the same soil. In support of Objective 2, ARS researchers at Logan, Utah, continued research to characterize the alkaloid profiles from several Delphinium species that had not been investigated previously. Methyllycaconitine, the larkspur toxin most commonly associated with poisoning of cattle, was detected in most species tested. Additionally, two Delphinium species were collected over the growing season in 2020, 2021 and are currently being collected over the growing season of 2022 at nine different locations to determine how alkaloid concentrations change over the growing season and between years and how they might vary at different locations. Under Sub-objective 2.2, ARS researchers at Logan, Utah, surveyed several Astragalus species for swainsonine and selenium and are in the initial stages of preparing a publication. Under Sub-objective 2.4, ARS researchers at Logan, Utah, have completed an analysis of the macro and micro-nutrients from treated plants and are in the initial stages of preparing a publication. In support of Sub-objective 2.7, ARS researchers at Logan, Utah, have identified herbarium collections representing the taxa of interest and initial collections have started. Chemical analysis has been initiated on select samples. In support of Objective 3, ARS researchers at Logan, Utah, collected earwax in the fall of 2021 from 69 pregnant cows that grazed pastures containing teratogenic lupine plants throughout the summer of 2021. Nine of the 69 cows gave birth to malformed calves (terata). The earwax samples were analyzed for teratogenic alkaloids. Concentrations of teratogenic alkaloids in earwax samples were found to not correlate with cows that gave birth to malformed calves and those that had normal births. Under Sub-objective 3.4, ARS researchers at Logan, Utah, determined that inhibition of serum mannosidase by swainsonine is variable and under these conditions, correlation with tissue or species susceptibility to locoweed-induced disease is not apparent. More work is needed to increase sensitivity and better defining the inhibitory constant (Ki), as the marked variation is both tissue and species reaction to mannosidase inhibition suggests there are differences in swainsonine mannosidase binding affinity. Additionally under Sub-objective 3.4, ARS researchers at Logan, Utah, concluded studies to evaluate the carcinogenic nature of six different dehydropyrrolizidine alkaloids using a P53 knockout mouse model. Dosing of the last two experimental groups has begun and those animals will finish later this year. The histological analyses of previously treated mice are mostly completed. In support of Objective 4, ARS researchers at Logan, Utah, conducted an experiment to determine if cattle would decrease their overall feed intake after being poisoned by larkspur (Delphinium spp.). Samples are in the process of being analyzed for nutrition content and data is being prepared for statistical analysis. Under Sub-objective 4.3, ARS researchers at Logan, Utah, demonstrated that feeding high selenium containing forage to sheep causes early disruption of spermatogenesis resulting in decreased sperm motility and increased morphological abnormalities without causing other signs of toxicity. Similar trials in cattle had very little negative impact on sperm quality, however clinical signs of chronic selenium poisoning were observed. Testicular lesions were examined microscopically and have been classified as an early disruption of spermatogenesis. A grading method was also developed, and the second review and grading evaluation of these studies was completed. This histology work will be correlated with chemical analysis and those publications are in preparation. In support of Objective 5, ARS researchers at Logan, Utah, demonstrated that larkspur toxicity is both age and sex dependent in cattle. After evaluating the past 15 years of research, ARS researchers at Logan, Utah, have rejected their hypothesis that larkspur susceptibility in Angus cattle is a heritable trait. Efforts have been redirected towards using a mineral mix to reduce the impact of larkspur on cattle. ACCOMPLISHMENTS 01 Mineral-salt supplementation protects against larkspur poisoning in cattle. Larkspurs (Delphinium spp.) are toxic to cattle and cause the livestock industry millions of dollars in losses every year. Finding inexpensive solutions to help reduce cattle losses would be beneficial to the livestock producer and the food supply chain. In pen feeding trials, ARS researchers in Logan, Utah, found animals supplemented with a mineral-salt were more resistant to larkspur toxicosis than non- supplemented animals. Animals supplemented with the mineral during a rangeland grazing study were found to consume less larkspur. These results suggest that a good mineral supplementation program could provide a protective effect for animals grazing in larkspur-infested rangelands. 02 A new method for detection and quantification of larkspur toxins. Larkspurs contain toxic norditerpene alkaloids, which have most recently been analyzed by a Fourier infrared spectroscopic method. ARS researchers in Logan, Utah, developed an alternative method to measure toxic and total alkaloids was developed using flow-injection mass spectrometry and validated to replace the older method. The new method is more rapid and requires less sample preparation than the previous method. The new method will provide better and less expensive support for research projects and diagnostic cases. 03 Diazepam as a treatment for water hemlock poisoning. Water hemlock (Cicuta maculata) is one of the most toxic plants in north America to livestock and humans. ARS researchers in Logan, Utah, evaluatded therapeutic options to determine what drug is best for treating livestock poisoned by water hemlock. The actions of several benzodiazepines and barbiturates on water hemlock poisoning in goats were compared. The benzodiazepine, diazepam, was effective at managing the clinical signs of water hemlock poisoning. The results of this research suggest that diazepam could be an effective treatment for water hemlock poisoning in livestock species and humans. 04 Swainsonine containing Ipomoea species and their association with fungal symbionts. Understanding host symbiont relationships is critical to our basic understanding of the synthesis of some plant toxins such as swainsonine. ARS researchers in Logan, Utah, in collaboration with New Mexico State University researchers investigated the association of the fungal symbiont in its host using different types of microscopy. This research provides valuable basic information to other scientific researchers about the nature of the symbiosis between a host (plant) and a symbiont (fungus). Understanding these associations may provide important understanding of mechanisms to disrupt the association, which would render the plant less toxic. 05 Swainsonine containing Ipomoea species. Understanding the chemical composition of plant taxa is required to better predict risk of poisoning and make recommendations to reduce livestock losses. ARS researchers in Logan, Utah, in collaboration with other researchers surveyed over 200 Ipomoea species for the toxin swainsonine. Swainsonine was identified in 32 species, most of which were previously not known to contain swainsonine. The information learned from this research may be helpful to extension agents and range scientists at various government agencies, as well as livestock producers, and other investigators studying toxic plants and natural products. This research has significant impact as it has saved the lab several hundred-man hours and tens of thousands of dollars that would have been used making field collections. 06 Salt desert shrub plant communities are influenced by precipitation. Drought conditions are altering vegetation dynamics on salt desert shrub plant communities. There is a lack of long-term data sets following vegetation dynamics on these plant communities. ARS researchers in Logan, Utah, examined thirty years of plant foliar cover and found that native shrub cover and warm-season grass cover increased when cool-season precipitation was available. Climatic conditions were a dominant influence on the vegetation in the salt desert shrub plant community. This data will provide valuable information for future science-based policy decisions with regards to the management of salt desert shrub plant communities. 07 Broom snakeweed does not directly cause late term abortions in cattle. Broom snakeweed (Gutierrezia sarothrae) and threadleaf snakeweed (G. microcephala) are found on many rangelands in western North America, and there are field reports that pregnant cows that graze snakeweeds may abort calves. Snakeweeds are generally unpalatable; however, animals will graze them when other forage is not available. ARS researchers in Logan, Utah, fed late-term pregnant cattle with plant material or with solvent extracted compounds from snakeweeds to test the extracts for abortifacient activity in late-term pregnant cattle. Neither the plant material, nor the dosed extracts, appear to be able to directly cause abortions in cattle. This research suggests that broom snakeweed plants are unlikely to be directly responsible for cattle abortions observed in cattle grazing snakeweed infested rangelands. It is more likely that cattle may be affected by rumen toxicity and/or might suffer from poor nutritional factors given the lack of quality forage available on rangelands with high snakeweed infestation. 08 Identification of two death camas chemotypes in a plant population. Foothill death camas (Zigadenus paniculatus) is a bulbous perennial forb that is toxic to both sheep and cattle. A population of death camas with two different chemical profiles (chemotypes) was found growing within the same location. ARS researchers in Logan, Utah, conducted experiments to determine if there was a difference in toxicity between the two chemotypes in multiple species of animals. Based on the results of the study, caution should be taken when livestock are grazing death camas, as both chemotypes appear to pose a similar risk of poisoning to grazing livestock.

Impacts
(N/A)

Publications

Spackman, C., Stonecipher, C.A., Panter, K.E., Villalba, J.J. 2021. Grazing rotation on restored rangeland as a new tool for medusahead control. Western North American Naturalist. 81(3):438-442. https://doi.org/ 10.3398/064.081.0312.
Noor, A.I., Nava, A., Neyaz, M., Cooke, P., Creamer, R., Cook, D. 2021. Ectopic growth of the Chaetothyriales fungal symbiont on Ipomoea carnea. Botany. 99(10):619-627. https://doi.org/10.1139/cjb-2021-0037.
Stegelmeier, B.L. 2022. Hemlock (poison hemlock - Conium maculatum; water hemlock - Cicuta spp.) In: Hovda, L.R., Benson, D., Poppenga, R.H., editors. Blackwell's Five-Minute Veterinary Consult Clinical Companion: Equine Toxicology. 1st Edition. Hoboken, NJ: John Wiley & Sons, Inc. p. 287-293.
Stegelmeier, B.L. 2022. Pyrrolizidine alkaloids. In: Hovda, L.R., Benson, D., Poppenga, R.H., editors. Blackwell's Five-Minute Veterinary Consult Clinical Companion: Equine Toxicology. 1st Edition. Hoboken, NJ: John Wiley & Sons, Inc. p. 336-343.
Stegelmeier, B.L. 2022. Locoweed (Astragalus and Oxytropis) poisoning in horses. In: Hovda, L.R., Benson, D., Poppenga, R.H., editors. Blackwell's Five-Minute Veterinary Consult Clinical Companion: Equine Toxicology. 1st Edition. Hoboken, NJ: John Wiley & Sons, Inc. p. 315-321.
Ruiz-Barrio, I., Guisado-Alonso, D., Bulnes-Gonzalez, V., Green, B.T. 2022. Isolated dilated pupil. The BMJ. Article 376. https://doi.org/10.1136/bmj- 2021-069133.
Welch, K.D., Green, B.T., Gardner, D.R., Stonecipher, C.A., Cook, D. 2022. Toxic plants. In: Gupta, R.C., editor. Reproductive and Developmental Toxicology. Third Edition. San Diego, CA: Academic Press. p. 933-953. https://doi.org/10.1016/B978-0-323-89773-0.00046-1.
Green, B.T., Stonecipher, C.A., Welch, K.D., Lee, S.T., Cook, D. 2022. Evaluation of diazepam as a drug treatment for water hemlock (Cicuta species) poisoning in Spanish goats. Toxicon. 205:79-83. https://doi.org/ 10.1016/j.toxicon.2021.12.003.
Habermehl, T., Underwood, K., Welch, K.D., Gawrys, S., Parkinson, K., Schneider, A., Masternak, M., Mason, J. 2022. Aging-associated changes in motor function are ovarian somatic tissue-dependent, but germ cell and estradiol independent in post-reproductive female mice exposed to young ovarian tissue. GeroScience. https://doi.org/10.1007/s11357-022-00549-9.
Neyaz, M., Gardner, D.R., Creamer, R., Cook, D. 2022. Localization of the swainsonine-producing Chaetothyriales symbiont in the seed and shoot apical meristem in its host Ipomoea carnea. Microorganisms. 10(3). Article 545. https://doi.org/10.3390/microorganisms10030545.
Neyaz, M., Das, S., Cook, D., Creamer, R. 2022. Phylogenetic comparison of swainsonine biosynthetic gene clusters among fungi. The Journal of Fungi. 8(4). Article 359. https://doi.org/10.3390/jof8040359.
Stonecipher, C.A., Ransom, C., Thacker, E., Welch, K.D., Gardner, D.R., Palmer, M. 2020. Herbicidal control of deathcamas (Zigadenus paniculatus). Weed Technology. 35(3):380-384. https://doi.org/10.1017/wet.2020.102.
Harrison, J.G., Beltran, L.P., Buerkle, C.A., Cook, D., Gardner, D.R., Parchman, T.L., Poulson, S.R., Forister, M.L. 2021. A suite of rare microbes interacts with a dominant, heritable, fungal endophyte to influence plant trait expression. The ISME Journal: Multidisciplinary Journal of Microbial Ecology. 15:2763-2778. https://doi.org/10.1038/s41396-021-00964-4.
Creamer, R., Hille, D.B., Neyaz, M., Nusayr, T., Schardl, C.L., Cook, D. 2021. Genetic relationships in the toxin-producing fungal endophyte, Alternaria oxytropis using polyketide synthase and non-ribosomal peptide synthase genes. The Journal of Fungi. 7(7). Article 538. https://doi.org/ 10.3390/jof7070538.
Machado, M., Queiroz, C.R.R., Wilson, T.M., Sousa, D.E.R., Castro, M.B., Saravia, A., Lee, S.T., Armien, A.G., Barros, S.S., Riet-Correa, F. 2021. Endemic Xanthium strumarium poisoning in cattle in flooded areas of the Araguari River, Minas Gerais, Brazil. Toxicon. 200:23-29. https://doi.org/ 10.1016/j.toxicon.2021.06.019.
Gaspar, A.O., Guizelini, C.C., Roberto, F.C., Difante, G.S., Brumatti, R.C. , Itavo, C.C., Lemos, R.A., Lee, S.T. 2021. Protodioscin levels in Brachiaria spp. in a sheep production system and a brief review of the literature of Brachiaria spp. poisoning in ruminants. Pesquisa Veterinaria Brasileira. 41. Article e06921. https://doi.org/10.1590/1678-5150-PVB-6921.
Marin, R.E., Gardner, D.R., Armien, A.G., Fortunato, R.H., Uzal, F.A. 2022. Intoxication of llamas by Astragalus punae in Argentina. Journal of Veterinary Diagnostic Investigation. 34(4):674-678. https://doi.org/10. 1177/10406387221094272.
Stonecipher, C.A., Green, B.T., Welch, K.D., Gardner, D.R., Fritz, S., Cook, D., Pfister, J.A. 2022. Mineral-salt supplementation to ameliorate larkspur poisoning in cattle. Journal of Animal Science. 100(5):01-14. Article skac133. https://doi.org/10.1093/jas/skac133.
Gardner, D.R., Green, B.T., Stegelmeier, B.L., Welch, K.D. 2022. Broom snakeweed extracts dosed to late-term pregnant cattle do not cause premature parturition. Poisonous Plant Research. 5:13-21. https://doi.org/ 10.26077/15eb-503b.
Stonecipher, C.A., Lee, S.T., Welch, K.D., Gardner, D.R., Cook, D. 2022. Identification of two death camas chemotypes within a population and evaluation of toxicity. Toxicon. 215:6-10. https://doi.org/10.1016/j. toxicon.2022.05.047.
Stonecipher, C.A., Thacker, E., Ralphs, M.H. 2022. Relative influence of precipitation and grazing on a salt desert shrub plant community. Western North American Naturalist. 88(2):245-253.
Quach, Q.N., Gardner, D.R., Clay, K., Cook, D. 2022. Phylogenetic patterns of swainsonine presence in morning glories. Frontiers in Microbiology. 13. Article 871148. https://doi.org/10.3389/fmicb.2022.871148.
Diniz, W.J., Gerd, B., Klopfenstein, J.J., Gultekin, Y., Davis, T.Z., Ward, A.K., Hall, J.A. 2021. Supranutritional maternal organic selenium supplementation during different trimesters of pregnancy affects the muscle gene transcriptome of newborn beef calves in a time-dependent manner. Genes. 12(12). Article 1884. https://doi.org/10.3390/genes12121884.
Hall, J.A., Isaiah, A., McNett, E.L., Klopfenstein, J.J., Davis, T.Z., Suchodolski, J.S., Bobe, G. 2022. Supranutritional selenium-yeast supplementation of beef cows during the last trimester of pregnancy results in higher whole-blood selenium concentrations in their calves at weaning, but not enough to improve nasal microbial diversity. Animals. 12(11). Article 1360. https://doi.org/10.3390/ani12111360.
Gardner, D.R., Lee, S.T., Cook, D. 2021. Rapid quantitative analysis of toxic norditerpenoid alkaloids in larkspur (Delphinium spp.) by flow injection - electrospray ionization - mass spectrometry. Poisonous Plant Research. 4:10-19. https://doi.org/10.26077/jy40-h384.
Clemensen, A.K., Villalba, J.J., Lee, S.T., Provenza, F.D., Duke, S.E., Reeve, J. 2022. How do tanniferous forages influence soil processes in forage cropping systems? Crop, Forage & Turfgrass Management. 8. Article e20166. https://doi.org/10.1002/cft2.20166.

Progress 10/01/20 to 09/30/21

Outputs
PROGRESS REPORT Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. In support of Objective 1, ARS scientists in Logan, Utah, established study plots at two locations and sprayed them with herbicides to determine if herbicides can aid in the establishment of newly seeded grass species in revegetated rangelands infested with poisonous pants. The first- and second-year evaluations have occurred. Study plots were also established at two locations and sprayed with herbicides to determine their efficacy in controlling death camas, and to determine if the toxicity of death camas changes due to herbicide treatment. Initial evaluations indicated that the herbicides 2,4-D, Crossbow, and Plateau were effective in controlling death camas, and there was not a difference between the early vegetative and flowering application time. In support of Objective 2, ARS scientists in Logan, Utah, continued research to determine the alkaloid profiles from several Delphinium species that had not been investigated previously. Methyllycaconitine, the larkspur toxin most commonly associated with poisoning of cattle was detected in most species. ARS scientists in Logan, Utah, surveyed several Astragalus species for swainsonine and selenium. Under Sub-objective 2.4 ARS scientists in Logan, Utah, have completed the macro and micro- nutrient analyses of the plants. Under Sub-objective 2.7, herbarium collections representing the taxa of interest have been identified and initial collections have been started. In support of Sub-objective 3.2, ARS scientists in Logan, Utah, conducted a series of studies to identify the major diterpene acids in broom snakeweed and their metabolites in serum. A manuscript describing the chemotypes in two snakeweed species was published. Large sample collections of the two most prominent chemotypes were collected and extracts were prepared for dosing in cattle. In vivo testing of both chemotypes in late-term pregnant cattle was completed. One of the chemotypes was found to be extremely toxic to the bovine rumen. Neither chemotype was found to induce abortions in the cattle. A manuscript summarizing the results is in preparation. Under Sub-objective 3.3, studies demonstrated that the in vitro inhibition of serum mannosidase by swainsonine in different animal species correlates with in vivo swainsonine toxicosis. Serum mannosidase activity and sensitivity to swainsonine has been characterized in horses, cows, goats and sheep. Studies to further characterize the inhibition of serum mannosidase by swainsonine are being conducted. Under Sub-objective 3.4, ARS scientists in Logan, Utah, further evaluated the carcinogenicity of specific pyrrolizidine alkaloids, including studying the carcinogenicity of purified individual toxins in a P53 knockout mouse model. In support of Objective 4, studies were conducted to characterize the effect of low-dose selenium intake in cattle and sheep. Mineral, biochemical, and histological analyses of the samples are underway. Additionally, ARS scientists in Logan, Utah, measured the therapeutic actions of several drugs for the control of water hemlock poisoning in a goat model. This research identified diazepam as a good drug treatment for goats acutely poisoned by water hemlock. This research suggests that diazepam can be used as an effective treatment for water hemlock poisoning in livestock species, and potentially humans. In support of Objective 5, ARS scientists in Logan, Utah, continue to determine if there is a genetic contribution to the susceptibility of cattle to larkspur poisoning. The ability of cattle to pass along genes to their offspring that would result in either susceptibility, or resistance, to larkspur poisoning is being further evaluated. Additionally, grazing studies were conducted with cattle previously characterized as susceptible or resistant to larkspur poisoning in a pen setting, to determine if there is a difference in their susceptibility in a grazing setting as well. Also, a grazing study was conducted to determine if good, or poor, mineral supplementation can affect susceptibility of cattle to larkspur poisoning. Record of Any Impact of Maximized Teleworking Requirement: Maximum telework resulted in the following impacts on research in fiscal year (FY) 21. Attendance at several national and international meetings by ARS scientists in Logan, Utah, was prohibited. This impeded our ability to participate in technology transfer at these meetings. In many instances, ARS scientists in Logan, Utah, were unable to make the necessary travel arrangements to collect plants needed for analyses and pen studies. Additionally, some grazing studies were not able to be completed due to travel restrictions. These restrictions will result in a one-year delay in accomplishing our research efforts. The maximized telework requirements did not allow for ARS scientists in Logan, Utah, to interact as needed in person with, and provide support to, livestock producers and extension agents who needed support for plant poisoning cases. Furthermore, the restrictions for working at the laboratory, significantly reduced the ability of the scientists to conduct normal research studies. Thus, the productivity of the laboratory has significantly been reduced during the COVID-19 pandemic. ACCOMPLISHMENTS 01 Acute liver toxicity in cattle by Salvia reflexa. The weedy plant Salvia reflexa was identified by ARS scientists in Logan, Utah, as the cause of poisoning in cattle by weed-contaminated alfalfa hay that had resulted in the death of 165 cattle from a herd of 500. Four toxic compounds were identified, and a direct link was established to implicate Salvia reflexa as the toxic weed in the contaminated hay. Salvia toxicity was confirmed in mice, goats, and cattle. The identification of the cause of poisoning allowed the cattle owners to recover the losses which ⿿saved the ranch⿝. This is the first report of Salvia causing liver injury, and this information will be useful to veterinary practitioners and diagnostic laboratories in solving future cases where Salvia poisoning may be involved. 02 Herbarium specimens as a tool to investigate phytochemical composition. Understanding the chemical composition of plant taxa is required to better predict risk and make recommendations to reduce livestock losses. ARS researchers in Logan, Utah, summarized how herbarium specimens can be used as a tool to facilitate poisonous plant research. Herbarium specimens have been used to characterize the chemical composition of hundreds of species representing several groups (genera) of plants. The information learned from these phytochemical screens has been helpful to extension agents and range scientists at the various government agencies, as well as livestock producers, and other investigators studying toxic plants and natural products. This research has significant impact as it can save several hundred-man hours and tens of thousands of dollars that would be required to make field collections of a similar extent. 03 Soil amendments reduce the uptake of selenium by forages growing on seleniferous soils. ARS scientists in Logan, Utah, treated high selenium-containing soils from reclaimed mine sites with various amendments in an attempt to reduce the uptake of selenium by forages that grow on these sites, as forages grown on these soils can be toxic to livestock. The addition of iron as an amendment to high selenium soil resulted in 60 to 90% decrease in selenium concentrations in several forages, while simultaneously increasing the biomass of desired forages. The information obtained from this study indicates that iron treatment of soils with high selenium content can be used to decrease selenium concentrations in forages growing on these soils, which would decrease the risk to livestock, and wildlife, grazing on these ranges.

Impacts
(N/A)

Publications

Stegelmeier, B.L. 2020. Bracken fern poisoning in animals. Merck Veterinary Manual. 1:1-6.
Stegelmeier, B.L. 2020. Sweet clover poisoning in animals. Merck Veterinary Manual. 1:1-6.
Stegelmeier, B.L., Davis, T.Z., Clayton, M.J., Gardner, D.R. 2020. Identifying plant poisoning in livestock in North America. Veterinary Clinics of North America. 36:661-671. https://doi.org/10.1016/j.cvfa.2020. 08.001.
Stegelmeier, B.L., Davis, T.Z., Clayton, M.J. 2020. Neurotoxic plants that poison livestock. Veterinary Clinics of North America. 36:673-688. https:// doi.org/10.1016/j.cvfa.2020.08.002.
Stegelmeier, B.L., Davis, T.Z., Clayton, M.J. 2020. Plant-induced reproductive disease, abortion and teratology in livestock. Veterinary Clinics of North America. 36:735-743. https://doi.org/10.1016/j.cvfa.2020. 08.004.
Clayton, M.J., Davis, T.Z., Knoppel, E.L., Stegelmeier, B.L. 2020. Hepatotoxic plants that poison livestock. Veterinary Clinics of North America. 36:715-723. https://doi.org/10.1016/j.cvfa.2020.08.003.
Stegelmeier, B.L., Davis, T.Z., Clayton, M.J. 2020. Plant induced photosensitvity and dermatitis in livestock. Veterinary Clinics of North America. 36:725-733. https://doi.org/10.1016/j.cvfa.2020.08.008.
Stegelmeier, B.L., Davis, T.Z., Clayton, M.J. 2020. Plants containing urinary tract, gastrointestinal, or miscellaneous toxins that affect livestock. Veterinary Clinics of North America. 36:701-713. https://doi. org/10.1016/j.cvfa.2020.08.006.
Davis, T.Z., Stegelmeier, B.L., Clayton, M.J. 2020. Plant induced myotoxicity in livestock. Veterinary Clinics of North America. 36:689-699. https://doi.org/10.1016/j.cvfa.2020.08.005.
Panter, K.E., Stegelmeier, B.L., Gardner, D.R., Stonecipher, C.A., Lee, S. T., Kitchen, D., Brackett, A., Davis, C. 2021. Clinical, pathological and toxicological characterization of Salvia relexa (lance-leaf sage) poisoning in cattle fed contaminated hay. Journal of Veterinary Diagnostic Investigation. 33(3):537-547. https://doi.org/10.1177/1040638721995784.
Gardner, D.R., Panter, K.E., Stegelmeier, B.L., Stonecipher, C.A. 2021. Hepatotoxicity in cattle associated with Salvia reflexa diterpenes, including 7-hydroxyrhyacophiline, a new seco-clerodane diterpene. Journal of Agricultural and Food Chemistry. 69(4):1251-1258. https://doi.org/10. 1021/acs.jafc.0c06390.
Cholich, L.A., Pistan, M.E., Torres, A.M., Ortega, H.H., Gardner, D.R., Bustillo, S. 2020. Cytotoxic activity induced by the alkaloid extract from Ipomoea carnea on primary murine mixed glial cultures. Toxicon. 188:134- 141. https://doi.org/10.1016/j.toxicon.2020.10.019.
Cholich, L.A., Pistan, M.E., Torres, A.M., Ortega, H.H., Gardner, D.R., Bustillo, S. 2020. Characterization and cytotoxic activity on glial cells of alkaloid-enriched extracts from pods of the plants Prosopis flexuosa and Prosopis nigra (Fabaceae). Revista De Biologa Tropical. 69(1): 197-206. https://doi:10.15517/RBT.V69I1.43515.
Cook, D., Lee, S.T., Gardner, D.R., Molyneux, R.J., Johnson, R.L., Taylor, C.M. 2021. The use of herbarium voucher specimens to investigate phytochemical composition in poisonous plant research. Journal of Agricultural and Food Chemistry. 69(14):4037-4047. https://doi.org/10.1021/ acs.jafc.1c00708.
Oliveira, C.A., Riet-Correa, G., Lima, E., Medeiros, R., Miraballes, C., Pfister, J.A., Gardner, D.R., Cook, D., Riet-Correa, F. 2021. Toxicity of the swainsonine-containing plant Ipomoea carnea subsp. fistulosa for goats and sheep. Toxicon. 197:40-47. https://doi.org/10.1016/j.toxicon.2021.04. 013.
Stonecipher, C.A., Spackman, C., Panter, K.E., Villalba, J.J. 2021. The use of a herbicide as a tool to increase livestock consumption of medusahead (Taeniatherum caput-medusae). Invasive Plant Science and Management. 14(2):106-114. https://doi.org/10.1017/inp.2021.12.
Clemensen, A.K., Villalba, J.J., Rottinghaus, G.E., Lee, S.T., Provenza, F. D., Reeve, J.R. 2020. Do plant secondary metabolite-containing forages influence soil processes in pasture systems?. Agronomy Journal. 112(5) :3744-3757. https://doi.org/10.1002/agj2.20361.
Martinez, A., Cook, D., Lee, S.T., Sola, D., Bain, L., Borrelli, L., Acin, C., Gardner, D.R., Robles, C. 2020. Fatal stagger poisoning by consumption of Festuca argentina (speg.) Parodi in goats from Argentine Patagonia. Toxicon. 185:191-197. https://doi.org/10.1016/j.toxicon.2020.08.004.
Cane, J., Gardner, D.R., Weber, M. 2020. Neurotoxic alkaloid in pollen and nectar excludes generalist bees from foraging at death-camas, Toxicoscordion paniculatum (Melanthiaceae). Biological Journal of the Linnean Society, London. 131(4):927-935. https://doi.org/10.1093/ biolinnean/blaa159.
Larsen, R.E., Cook, D., Gardner, D.R., Lee, S.T., Shapero, M., Althouse, L. , Dennis, M., Forero, L.C., Davy, J.S., Rao, D.R., Horney, M., Brown, K., Rigby, C.W., Jensen, K.B. 2021. Seasonal changes in forage nutrient and toxicity levels on California central coast rangelands: a preliminary study. Grasslands. 31(1):15-24.

Progress 10/01/19 to 09/30/20

Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. In support of Sub-objective 1.1, ARS scientists evaluated numerous herbicides to determine if they will aid in establishment of newly seeded grass species in revegetated rangelands infested with annual grasses that also contain populations of poisonous plants (e.g., Lupinus). Plots were established at two locations and sprayed with herbicides. The first-year evaluations occurred last summer. The second-year evaluations will occur later this summer if allowed due to maximized telework travel restrictions. Under Sub-objective 1.2, ARS scientists evaluated numerous herbicides to determine efficacy in controlling death camas and to determine if the toxicity of death camas changes due to herbicide treatment. Plots were established at two locations and sprayed with herbicides. Plots were evaluated 10 days after herbicide treatment and death camas plants were collected for chemistry analysis. The herbicides 2,4-D, Crossbow, and Plateau were effective in controlling death camas and there was no difference between the early vegetative and flowering application time. A manuscript has been submitted for publication in a peer reviewed journal. Under Sub-objective 1.3, ARS scientists collected and analyzed samples from an experiment in which alfalfa, intermediate wheat grass, and western aster were grown on selenium-contaminated soils. Additionally, samples were collected and analyzed from feeding trials in which rams were fed a high selenium-containing diet. In support of Sub-objective 2.1, ARS scientists continued research to determine the toxic larkspur alkaloid profiles from numerous, previously uncharacterized Delphinium species. Methyllycaconitine, the larkspur toxin most commonly associated with poisoning of cattle, was detected in most species with varying ratios of the toxic to non-toxic-type alkaloids. Under Sub-objective 2.2, ARS scientists surveyed several Astragalus species for selenium. Selenium was detected in several species. In support of Sub-objective 3.2, ARS scientists identified the major diterpene acids in broom snakeweed, and the common metabolites found in serum of animals fed broom snakeweed. Work has been completed on defining the chemotypes in two broom snakeweed species. Samples have been collected throughout Wyoming, Colorado, Texas, New Mexico and Utah. Plants were taxonomically identified and then classified into eight different chemotypes based on the diterpene acid profiles. The completed structural identities of 21 diterpene acids isolated from the two broom snakeweed species has been completed. A publication has been submitted and is under review. Under Sub-objective 3.3, ARS scientists characterized and compared the serum mannosidase activity and sensitivity to the toxin swainsonine in horses, cows, goats, and sheep. Under Sub- objective 3.4, ARS scientists evaluated riddelliine in P53 knockout mice. A detailed examination for cancer-type lesions has been performed. Approximately 40% of the mice were euthanized early and several had hepatic and other tissue neoplastic diseases. In support of Sub-objective 4.2, ARS scientists determined that the plant Salvia reflexa contains hepatotoxic compounds. One publication describing the case history of poisoning by Salvia-contaminated hay has been submitted for publication in a peer reviewed journal. A second publication on chemical identification of the toxins is being prepared. Under Sub-objective 4.3, ARS scientists analyzed samples from animals fed high selenium containing diets and are working on the histology analyses of the samples. In support of Sub-objective 5.2, ARS scientists continue to determine the susceptibility, or resistance, of cattle to larkspur poisoning. Susceptible and resistant cows and heifers were inseminated with semen from similarly responding bulls. After maximum telework concludes, the calves will be evaluated to determine their susceptibility to larkspur. Accomplishments 01 Analysis of rumen contents and ocular fluid for toxic alkaloids from goats and cows dosed with larkspur, lupine, and death camas. Larkspurs, lupines, and death camas can be acutely toxic to livestock and are serious poisonous plant problems in western North America. ARS scientists in Logan, Utah, treated goats and cows with sub-lethal amounts of larkspur, lupine, and death camas. Rumen contents and ocular fluid samples were collected from these animals, and analytical methods were developed for the detection of toxic alkaloids in these samples. The toxins were detected in the rumen contents and ocular fluid samples from the goats and cows dosed with larkspur, lupine, and death camas. In addition, results from a case report where rumen contents were analyzed from a cow that was suspected to have died due to larkspur was reported. This demonstrates the utility of the methods described for the diagnosis of acute plant poisonings and will be valuable information for extension agents and veterinarians, especially diagnostic laboratories to aid in the diagnosis of poisoned animals, as well as livestock producers. 02 Evaluation of earwax, hair, oral fluid, and nasal mucus as noninvasive specimens to determine livestock exposure to poisonous plants. Poisoning of livestock by plants often goes undiagnosed because there is a lack of appropriate or available specimens for analysis. ARS researchers at Logan, Utah, detected larkspur alkaloids in the earwax, hair, oral fluid, and nasal mucus in cattle that were administered single doses of several species of larkspur plants. Lupine alkaloids were detected in the earwax, hair, oral fluid, and nasal mucus in cattle that were administered a single dose of lupine plants. In addition, alkaloids from lupine were detected in the earwax of cattle that had grazed in lupine-infested rangelands. The advantage of using earwax, hair, oral fluid, and nasal mucus for chemical analysis is that these biological specimens are noninvasive and are simple to collect, no special equipment is required, and untrained personnel can easily collect the samples for analysis. 03 Comparison of the geographical and seasonal variation in the toxins in foothill death camas plants. Death camas is a common poisonous plant in North America with plants occurring in a wide variety of habitats with species of toxic concern occurring primarily in meadows, grasslands, shrublands, and mountains. ARS scientists in Logan, Utah, compared the concentration of the known toxins in death camas in the different plant parts, over the growing season and across several locations. The results suggest that the toxic risk associated with death camas is greatest in the early vegetative growth stages followed by the flower and pod stages. There is a toxic risk to livestock as long as the plant is present, and caution should be taken when grazing livestock in areas with death camas as long as the plant is green. A similar toxic risk was observed in all locations evaluated. This information will be helpful to extension agents and range scientists at the various government agencies, as well as livestock producers. 04 Comparison of the geographical and seasonal variation in the toxins in water hemlock plants. Water hemlock is one of the most toxic plants in North America. ARS scientists at Logan, Utah, compared the variation in the toxic compounds in the different plant parts and water hemlock populations across western North America. There is a difference in the amount of the toxins in different plant parts, with the tubers from water hemlock being the most significant risk to poison livestock. The results also suggest that although there is variation in toxin concentration from location to location, all water hemlock populations across western North American likely pose a similar poisoning risk to livestock. This information will be helpful to extension agents and range scientists at the various government agencies, as well as livestock producers. 05 Comparison of Astragalus lentiginosus and Ipomoea carnea poisoning in goats. The toxin swainsonine, found in some Astragalus and Oxytropis (i. e., locoweed) species, is a potent cellular toxin that often poisons many livestock throughout the world every year. Other toxic plant genera, such as some Ipomoea species, also contain swainsonine as well as calystegines which are similar toxic alkaloids. The toxicity of calystegines is poorly characterized. ARS scientists in Logan, Utah, directly compared A. lentiginosus and I. carnea poisoning in goats to better characterize the role of the calystegines. The findings suggest that I. carnea-induced clinical signs and lesions are due to swainsonine and that calystegines contribute little, or nothing, to toxicity in goats in the presence of swainsonine. Understanding the contribution of different active compounds to toxicity aids in diagnosis. This information will be helpful to veterinarians, extension agents and range scientists at the various government agencies, as well as livestock producers. 06 Evaluation of the lethality/toxicity of water hemlock in goats. Water hemlock is one of the most toxic plants to livestock and humans. However, little is known regarding the amount of plant required to cause death. ARS investigators in Logan, Utah, determined the amount of water hemlock needed to kill a goat. The results from this study suggest that 1�2 fresh tubers would be lethal to goats, which is consistent with case reports of human poisonings. This information is useful as it provides a relative risk assessment of the plant. This information will be helpful to veterinarians, extension agents and range scientists at the various government agencies, as well as livestock producers. 07 The toxicity of Isocoma plant species was determined in cattle. Isocoma plant species often cause significant livestock losses in the southwestern United States. The toxicity of different Isocoma species in cattle has not been previously determined. ARS researchers at Logan, Utah, compared the relative toxicity of different Isocoma species while also determining the concentrations of the putative toxins in the plant material. This information is valuable for land managers, veterinarians and extension agents when determining the risk associated with grazing certain rangelands and when diagnosing potential cases of poisoning by Isocoma species. 08 Comparative process to evaluate toxicity of riddelliine in primary mouse, rat and chick hepatocytes developed. Dehydropyrrolizidine alkaloid (DHPA) producing plants commonly poison livestock, wildlife and humans. Poisoning occurs when DHPAs are ingested as feed or food, or when they contaminate medicinal or herbal products. Direct toxicologic comparison of individual DHPAs is essential to estimate their actual health risks, but this has been problematic due to varying models and difficulties in DHPA isolation or synthesis. ARS scientists in Logan, Utah, characterized the effect of riddelliine, a common DPHA, on primary mouse, rat, and chick hepatocyte cultures, with the aim of developing a suitable, sensitive model for assessing DHPA-related cytotoxicity. This model may be useful to directly compare panels of DHPAs, including rare or difficult to isolate alkaloids. This information will valuable for scientists studying DHPAs, extension agents and veterinarians at diagnostic laboratories. 09 Characterization of the development of tolerance of cattle to larkspur poisoning. The severity of larkspur poisoning depends on the genetic background of the cattle, the amount of plant consumed, the rate of consumption, and the concentrations of toxic alkaloids in the plants. Identifying cattle which are naturally resistant to larkspur intoxication would improve grazing animal welfare on these rangelands and reduce losses to poisonous plants. ARS researchers at Logan, Utah, have identified and characterized the development of tolerance to larkspur alkaloids by the cattle. This information will be useful for scientists studying larkspur toxicosis as well as land managers, extension agents, and livestock producers. 10 Evaluation of the toxic principle found in white snakeroot and rayless goldenrod in cell culture models. Tremetone is a putative toxin in white snakeroot and rayless goldenrod. ARS scientists in Logan, Utah, tested the actions of these toxins in two different cell lines. Tremetone did not require activation to be toxic to the cells. This suggests that tremetone is directly toxic without metabolism. This work helps in the understanding of the mechanism by which white snakeroot and rayless goldenrod are toxic to animals, which will aid in the development of therapies for poisoned animals. 11 Analysis of Convolvulaceous (morning glory) species for bioactive alkaloids that cause poisoning. Some Convolvulaceous species have been reported to contain several bioactive principles that are toxic including swainsonine, ergot alkaloids, and indole diterpene alkaloids. ARS researchers at Logan, Utah, analyzed thirty Convolvulaceous species for these alkaloids. The ergot alkaloids were detected in 18 species, the indole diterpenes were detected in 10 species, and swainsonine was detected in two species. The data suggested that there was an association between the occurrence of the respective bioactive principle and the genetic relatedness of the respective host plant species. This information provides a reference list of potentially toxic species and provides a better understanding of the composition of bioactive principles in some Convolvulaceous species. 12 An evaluation of the susceptibility of goats to larkspur poisoning. Larkspurs are a major cause of cattle losses in western North America, whereas sheep have been shown to be resistant to larkspur toxicosis. Goats are often used as a small ruminant model to study poisonous plants, even though they can be more resistant to some poisonous plants. It is not known how susceptible goats are to the adverse effects of larkspurs. ARS scientists in Logan, Utah, evaluated the susceptibility of goats to larkspur poisoning. None of the goats treated in this study, exhibited clinical signs typical of larkspur poisoning. We conclude that goats are resistant to larkspur toxicosis, and thus it is very unlikely that goats would be poisoned by larkspur. 13 Detection of swainsonine-producing endophytes in South American Astragalus species. Swainsonine, a toxic indolizidine alkaloid, has been detected in several South American Astragalus species. ARS researchers in Logan, Utah, in collaboration with colleagues from Argentina, investigated several swainsonine-containing species for the presence of a fungal symbiont. A fungal symbiont, Alternaria section Undifilum, was detected by both culturing techniques and PCR in species containing swainsonine and was found to produce swainsonine. This is important information that is valuable to scientists studying plants that contain swainsonine, which includes the locoweeds found throughout the United States.

Impacts
(N/A)

Publications

Stegelmeier, B.L., Jones, M., Womack, C.P., Davis, T.Z., Gardner, D.R. 2019. North American hard yellow liver disease: an old problem readdressed. Poisonous Plant Research. 2:1-13.
Carvalho Nunes, L., Stegelmeier, B.L., Cook, D., Pfister, J.A., Gardner, D. R., Riet-Correa, F., Welch, K.D. 2019. Clinical and pathological comparison of Astragalus lentiginosus and Ipomoea carnea poisoning in goats. Toxicon. 171:20-28.
Stonecipher, C.A., Cook, D., Welch, K.D., Gardner, D.R., Pfister, J.A. 2020. Seasonal variation in toxic steroidal alkaloids of foothill death camas (Zigadenus paniculatus). Biochemical Systematics and Ecology. 90.
Welch, K.D., Stonecipher, C.A., Lee, S.T., Cook, D. 2020. The acute toxicity of water hemlock (Cicuta douglasii) in a goat model. Toxicon. 176:55-58.
Lee, S.T., Welch, K.D., Stonecipher, C.A., Cook, D., Gardner, D.R., Pfister, J.A. 2020. Analysis of rumen contents and ocular fluid for toxic alkaloids from goats and cows dosed larkspur (Delphinium berbeyi), lupine (Lupinus leucophyllus), and death camas (Zigadenus paniculatus). Toxicon. 176: 21-29.
Marin, R.E., Micheloud, J.F., Vignale, N.D., Gimeno, E.J., O'Toole, D., Gardner, D.R., Woods, L., Uzal, F.A. 2020. Intoxication by Astragalus garbancillo var. garbancillo in llamas. Journal of Veterinary Diagnostic Investigation. 32(3):467-470.
Green, B.T., Lee, S.T., Davis, T.Z., Welch, K.D. 2019. Microsomal activation, and SH-SY5Y cell toxicity studies of tremetone and 6- hydroxytremetone isolated from rayless goldenrod Isocoma pluriflora and white snakeroot Agertina altissima, respectively. Toxicon: X. 5.
Green, B.T., Pfister, J.A., Gardner, D.R., Welch, K.D., Cook, D. 2020. Dynamics of larkspur (Delphinium barbeyi) pellet consumption and tolerance of the inhibitory effects of larkspur alkaloids on muscle function in cattle. Poisonous Plant Research. 3:28-41.
Green, B.T., Gardner, D.R., Stonecipher, C.A., Lee, S.T., Pfister, J.A., Welch, K.D., Cook, D., Davis, T.Z., Stegelmeier, B.L. 2020. Larkspur poisoning of cattle: plant and animal factors that influence plant toxicity. Rangelands. 42(1):1-8.
Davis, T.Z., Green, B.T., Stegelmeier, B.L., Lee, S.T. 2020. The comparative toxicity of Isocoma species in calves. Toxicon: X. 5.
Stonecipher, C.A., Welch, K.D., Lee, S.T., Cook, D., Pfister, J.A. 2020. Geographical and seasonal variation in water hemlock (Cicuta maculata) toxins. Biochemical Systematics and Ecology. 89.
Welch, K.D., Stonecipher, C.A., Gardner, D.R., Green, B.T., Cook, D. 2020. An evaluation of the susceptibility of goats to larkspur toxicosis. Poisonous Plant Research. 3:19-27.
Pessoa, D.A., Lopes, J.R., Souza, E.M., Campos, E.M., Medeiros, R.M., Cook, D., Lee, S.T., Riet-Correa, F. 2019. Herbaspirillum seropedicae as a degrading bacterium of monofluoracetate: effects of its inoculation in goats by ingesting Amorimia septentrionalis and the concentrations of this compound in plants sprayed with the bacterium. Pesquisa Veterinaria Brasileira. 39(10):802-806.
Neyaz, M., Cook, D., Creamer, R. 2020. Molecular differentiation of Astragalus species and varieties from the Western United States: the chloroplast DNA bridge between evolution and molecular systematics. Poisonous Plant Research. 3:1-18.
Stonecipher, C.A., Lee, S.T., Green, B.T., Cook, D., Welch, K.D., Pfister, J.A., Gardner, D.R. 2019. Evaluation of noninvasive specimens to diagnose livestock exposure to toxic larkspur (Delphinium spp.). Toxicon. 161:33-39.
Heiling, J.M., Cook, D., Lee, S.T., Irwin, R.E. 2019. Pollen and vegetative secondary chemistry of three pollen-rewarding lupines. American Journal of Botany. 106(5):643�655.
Mendonca, F.S., Siva Filho, G.B., Chaves, H.A., Aires, L.D., Braga, T.C., Gardner, D.R., Cook, D., Buril, M.T. 2018. Detection of swainsonine and calystegines in Convolvulaceae species from the semiarid region of Pernambuco. Pesquisa Veterinaria Brasileira. 38(11):2044-2051.
Cook, D., Lee, S.T., Panaccione, D.G., Leadmon, C.E., Clay, K., Gardner, D. R. 2019. Biodiversity of Convolvulaceous species that contain ergot alkaloids, indole diterpene alkaloids, and swainsonine. Biochemical Systematics and Ecology. 86.
Stegelmeier, B.L., Reseager, W.S., Colegate, S.W. 2020. The comparative cytotoxicity of riddelliine in primary mouse, rat, and chick hepatocytes. Poisonous Plant Research. 3:43-57.
Martinez, A., Robles, C., Roper, J.M., Gardner, D.R., Neyaz, M., Joelson, N., Cook, D. 2019. Detection of swainsonine-producing endophytes in Patagonian Astragalus species. Toxicon. 117:1-6.
Vikuk, V., Young, C.A., Lee, S.T., Nagabhyru, P., Krischke, M., Mueller, M. J., Krauss, J. 2019. Infection rates and alkaloid patterns of different grass species with systemic Epiclo� endophytes. Applied and Environmental Microbiology. 85(17).
Spackman, C., Monaco, T.A., Stonecipher, C.A., Villalba, J.J. 2020. Plant silicon as a factor in Medusahead (Taeniatherum caput-medusae) invasion. Invasive Plant Science and Management.
Gardner, D.R., Cook, D., Larsen, S.W., Stonecipher, C.A., Johnson, R. 2020. Diterpenoids from Gutierrezia sarothrae and G. microcephala: chemical diversity, chemophenetics and implications to toxicity in grazing livestock. Phytochemistry. 178.
Salinas, L.M., Balseiro, A., Jiron, W., Peralta, A., Munoz, D., Fajardo, J. , Gayo, E., Martinez, I.Z., Riet-Correa, F., Gardner, D.R., Marin, J.F. 2019. Neurological syndrome in goats associated with Ipomoea trifida and Ipomoea carnea containing calystegines. Toxicon. 157:8-11.
Buroni, F., Gardner, D.R., Boabaid, F.M., Oliveira, L.G., De Nava, G., Lopez, F., Riet-Correa, F. 2020. Spontaneous abortion in cattle after consumption of Hesperocyparis (Cupressus) macrocarpa (Hartw.) Bartel and Cupressus arizonica (Greene) needles in Uruguay. Toxicon. 181:53-56.
Stonecipher, C.A., Ransom, C., Thacker, E., Welch, K.D. 2020. Herbicide control of broom snakeweed (Gutierrizia sarothrae). Poisonous Plant Research. 3:74-81.
Pfister, J.A., Cook, D., Lee, S.T., Gardner, D.R., Riet-Correa, F. 2020. Livestock preference for endophyte-infected or endophyte-free Oxytropis sericea, Ipomoea carnea, and Ipomoea asarifolia. Poisonous Plant Research. 3:58-73.

Progress 10/01/18 to 09/30/19

Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2. Approach (from AD-416): The livestock industry in the western United States loses over $500,000, 000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers. This is a new project which began in February 2019. This project continues research from a bridging project 2080-32630-013-00D. Under Sub-objective 1.1, ARS scientists at Logan, Utah, evaluated herbicides to determine if they will aid in establishment of newly seeded grass species in revegetated rangelands infested with annual grasses that also contain populations of poisonous plants (e.g., Lupinus). Plots were established at two locations and sprayed with herbicides. The first-year evaluations will occur later this summer. Under Sub-objective 1.2, the scientists evaluated herbicides to determine efficacy in controlling death camas, and if the toxicity of death camas changes due to herbicide treatment. Plots were established at two locations and sprayed with herbicides. Plots were evaluated 10 days after herbicide treatment and death camas plants were collected for chemical analysis. Under Sub- objective 1.3, ARS scientists conducted greenhouse studies to grow western aster, alfalfa, and intermediate wheat grass in seleniferous soils from contaminated phosphate mine sites. Amendments were added to the soil and the addition of zero valent iron decreased the uptake of selenium in each of the forages. Under Sub-objective 2.1, ARS scientists initiated research to determine norditerpene alkaloid profiles from numerous, previously uncharacterized Delphinium species. Methyllycaconitine, a primary larkspur toxin, was detected in most species with varying ratios of the toxic to non-toxic- type alkaloids. Under Sub-objective 2.2, ARS scientists surveyed several other Astragalus species for swainsonine. Swainsonine was not detected in any of the additional species surveyed. Under Sub-objective 2.5, the ARS scientists collected water hemlock plants from six different geographical locations in the western U.S. at the various phenological growth stages. The plant samples have been processed and chemically evaluated for cicutoxin concentrations. Under Sub-objective 2.6, ARS scientists collected death camas plants from two different geographical locations in the western USA at the various phenological growth stages. The plant samples have been processed and chemically evaluated for zygacine concentrations. Additionally, under this objective ARS scientists at Logan, Utah initiated a multi-year study in 2011 to measure plant density and life history of Delphinium andersonii populations in southern Idaho. In five of nine years, essentially no plants emerged and flowered because of drought conditions. During the four years when some plants emerged and flowered, plant densities were high enough to pose a serious threat to grazing cattle. Approximately 10 percent of the marked plants remained dormant for two to four years, then emerged when precipitation was favorable. Understanding the life history and weather conditions that promote Delphinium andersonii populations will enable livestock producers to better manage risk of cattle deaths. Under Sub-objective 3.1, ARS scientists initiated studies to evaluate several types of animal tissues/specimens, such as ear wax, nasal mucous and saliva, as potential matrices for the detection of exposure to poisonous plants, including: larkspur, lupine, death camas, and water hemlock. Under Sub-objective 3.2, ARS scientists continued research on the isolation and identification of potential toxins from broom snakeweed that may cause abortion in cattle. Plants have been collected, with most of the potential toxins isolated and identified from the major plants. Plants are now being classified by geographic location, species, and chemical types. Under Sub-objective 3.3, the scientists made progress evaluating serum mannosidase activity and sensitivity to swainsonine in horses, cows, goats and sheep. Under Sub-objective 3.4, the scientists established a mouse breeding colony of P53 knockout mice to be used in determining the carcinogenic potential of pyrrolizidine alkaloids. Over 150 heterozygous male mice have been dosed with control material, riddelliine and lasiocarpine and the mice are being monitored for cancer development. Under Sub-Objective 4.2, the ARS scientists continued research on the identification of the toxins in Salvia plants using bioassay-guided isolation of the toxic compounds. Under Sub-objective 4.3, the scientists fed male sheep (rams) with high selenium (Se) feeds for 12 weeks. When rams were fed greater than 10 parts per million (ppm) Se feed spermatogenesis was negatively impacted. There was a decrease in the percentage of progressively motile sperm and an increase in abnormal sperm. Additionally, under Objective 4, Convolvulaceous species have been reported to contain several bioactive principles thought to be toxic to livestock including the calystegines, swainsonine, ergot alkaloids, and indole diterpene alkaloids. To further explore the biodiversity of species that may contain indole diterpenes, ARS scientists analyzed several Convolvulaceous species (n=30) for indole diterpene alkaloids, representing four genera, Argyreia, Ipomoea, Stictocardia, and Turbina, that had been previously reported to contain ergot alkaloids. Ergot alkaloids were detected in 18 species representing all four genera screened. Indole diterpenes were detected in two Argyreia species and eight Ipomoea species, of the 18 that contained ergot alkaloids. Swainsonine was detected in two Ipomoea species. Additionally, under Objective 4, ARS scientists determined goat, sheep, and cattle preferences for endophyte positive or endophyte negative Oxytropis sericea, Ipomoea carnea, and Ipomoea asarifolia. Goats and sheep rejected all forage choices regardless of endophyte status, except for grass and alfalfa hay. Endophyte status had no influence on cattle forage preferences. Cattle rejected all Oxytropis sericea endophyte positive and endophyte negative choices, and preferred Ipomoea carnea to Ipomoea asarifolia regardless of endophyte status. Nutritional composition, including non-structural carbohydrate concentrations, did not explain cattle preferences. This work suggests that for these toxic plant species, endophyte status plays no part in preferences of grazing livestock. Under Sub-Objective 5.2, ARS scientists determined the susceptibility or resistance to larkspur poisoning of cattle. Susceptible and resistant heifers were artificially inseminated with semen from similarly responding bulls. We are currently waiting for some of these calves to be born. Calves from this last year are being trained and their susceptibility will be determined. Accomplishments 01 Larkspur poisoning is sex-dependent in yearling Angus cattle. Female cattle respond differently to larkspur than males. ARS scientists in Logan, Utah, tested yearling Angus bulls, steers and heifers (a total of 123 cattle) with the same dose of larkspur. The severity of the poisoning depended on the sex of the cattle. Heifers had a 3.3-fold increased risk of susceptibility to larkspur poisoning compared to bulls. The 3.3-fold greater relative risk for larkspur poisoning emphasizes the importance of the careful management needed when grazing Angus heifers on larkspur-infested rangelands. 02 Larkspur poisoning in cattle is age-dependent. ARS scientists in Logan, Utah, dosed Angus steers with the same dose of larkspur as yearlings and again when they were two years of age. The results from this experiment indicated that yearling steers are more susceptible to larkspur poisoning than two-year-old steers. There were also age- dependent changes in the ability of the steers to clear the larkspur alkaloid from their body as they aged. These results suggest that older cattle are more tolerant of larkspur and thus better suited to graze in larkspur-infested rangelands. 03 Evaluation of noninvasive specimens to determine livestock ingestion of toxic plants. Poisoning of livestock by plants often goes undiagnosed because there is a lack of appropriate or available specimens for analysis, especially in dead animals. ARS scientists in Logan, Utah, detected Lupine alkaloids in the earwax, hair, oral fluid, and nasal mucus in cattle that were administered a single dose of Lupinus leucophyllus. In addition, alkaloids from lupine were detected in the earwax of cattle that grazed lupine-infested rangelands. Larkspur alkaloids were detected in the earwax, hair, oral fluid, and nasal mucus in cattle that were administered single doses of Delphinium barbeyi and Delphinium ramosum. The advantage of using earwax, hair, oral fluid, and nasal mucus for chemical analysis is that these biological specimens are noninvasive and are simple to collect. Special equipment is not required, and untrained personnel can easily collect the samples for analysis. 04 Larkspurs contain mixtures of toxic alkaloids that differentially intoxicate cattle. Larkspurs contain mixtures of toxic alkaloids and these mixtures can change based upon the geographic location and species of the plants. A chemical fingerprint/chemotype for larkspur plants from six geographic locations was determined by ARS scientists in Logan, Utah. A model was developed to predict chemotype toxicity based upon alkaloid concentrations and alkaloid subtypes. Each of the six plant chemotypes was evaluated in cattle. Results from this experiment showed that a chemotype of D. geyeri (plains larkspur) possessed the greatest toxic potential, as was predicted by the model. 05 Correlation of available selenate with uptake by western aster. Western aster with potentially lethal amounts of selenium grow on historic reclaimed phosphate mine sites in the western U.S. Understanding the correlation between soil and forage selenium concentrations is limited. An ARS scientist in Logan, Utah, used a hydroponic model to demonstrate the correlation between solution selenate concentrations and leaf selenium concentrations in western aster. This information is helpful to regulatory agencies and mining officials to better understand the potential risk that soils with high selenate concentrations may present if selenium accumulator species, such as western aster, grow on these soils.

Impacts
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Publications

Martinez, A., Gardner, D.R., Cook, D., Gimeno, E.J., Robles, C.A. 2019. Potencial toxigenico de Astragalus pehuenches Niederl en Argentina. Revista de Ivestigaciones Agropecuaria. 44(3):378-383.
Koether, K., Lee, S.T., Belluci, R.S., Garcia, R., Pfister, J.A., Cunha, P. J., Rocha, N.S., Borges, A.S., Oliveira-Filho, J.P. 2019. Spontaneous poisoning by Palicourea marcgravii (Rubiaceae) in a sheep herd in southeastern Brazil. Toxicon. 161:1-3.
Lopes, J.R., Araujo, J.A., Pessoa, D.A., Lee, S.T., Cook, D., Riet-Correa, F., Medeiros, R.M. 2019. Neonatal mortality associated with sodium monofluoracetate in kids fed with colostrum from goats ingesting Amorimia septentrionalis. Pesquisa Veterinaria Brasileira. 39(3):163-167.
Stegelmeier, B.L., Colegate, S.M., Knoppel, E.L., Rood, K.A., Collett, M.G. 2019. Wild parsnip (Pastinaca sativa)-induced photosensitization. Toxicon. 167:60-66.
Stonecipher, C.A., Thacker, E., Welch, K.D., Ralphs, M.H., Monaco, T.A. 2019. Long-term persistence of cool-season grasses planted to suppress broom snakeweed, downy brome, and weedy forbs. Rangeland Ecology and Management. 72(2):266-274.
Green, B.T., Keele, J.W., Bennett, G.L., Gardner, D.R., Stonecipher, C.A., Cook, D., Pfister, J.A. 2019. Animal and plant factors which affect larkspur toxicosis in cattle: Sex, age, breed, and plant chemotype. Toxicon. 165:31-39.
Green, B.T., Keele, J.W., Gardner, D.R., Welch, K.D., Bennett, G.L., Cook, D., Pfister, J.A., Davis, T.Z., Stonecipher, C.A., Lee, S.T., Stegelmeier, B.L. 2019. Sex-dependent differences for larkspur (Delphinium barbeyi) toxicosis in yearling Angus cattle. Journal of Animal Science. 97(3):1424- 1432.
Green, B.T., Gardner, D.R., Pfister, J.A., Welch, K.D., Bennett, G.L., Cook, D. 2019. The effect of alkaloid composition of larkspur (Delphinium) species on the intoxication of Angus heifers. Journal of Animal Science. 97(3):1415-1423.
Green, B.T., Lee, S.T., Gardner, D.R., Welch, K.D., Cook, D. 2019. Bioactive alkaloids from plants poisonous to livestock in North America. Israel Journal of Chemistry. 59(5):351-359.