Location: Poisonous Plant Research2010 Annual Report
1a. Objectives (from AD-416)
Objective I: Pine Needles 1.1 Determine if isocupressic acid (ICA; the abortifacient compound in pine needles) concentration in pine needles is modulated by the environment. 1.2 Identify the matabolites of isocupressic acid in pine needles that cause abortions in cattle. Determine the biological mechanism, develop diagnostic techniques, and therapeutic procedures. 1.3 Determine factors that influence cattle consumption of pine needles and develop management practices to prevent abortion. Objective II: Broom Snakeweed 2.1 Identify the toxic and abortifacient compounds in broom snakeweed. 2.2 Describe the ecology of broom snakeweed, develop management and control guidelines to reduce incidence of poisoning and abortion in livestock. Objective III: Lupine 3.1 Isolate, identify, and evaluate toxicity and teratogenicity of lupine alkaloids which cause birth defects in calves born to cows that graze these plants. 3.2 Evaluate the role of genotype and environment on lupine alkaloids, and thus the relative toxicity of various species and populations of lupine. 3.3 Determine the physiological mechanism of lupine-induced birth defects and evaluate the maternal and fetal toxicokinetics of alkaloids. 3.4 Evaluate the influence of climate on population cycles of lupine. 3.5 Determine the importance of lupines as nutritional components for cattle during critical times of the year. 3.6 Identify conditions under which cattle graze various lupine species. Objective IV: Veratrum 4.1 Develop models to study the toxicokinetics, including clearance times, and toxicity of steroidal alkaloids in Veratrum californicum.
1b. Approach (from AD-416)
1.1 Data on environmental conditions will be collected at each site using local weather stations. ICA levels and environmental conditions will be correlated to determine if any patterns emerge. Soil samples will be collected at each site for future evaluation. 1.2 Samples of maternal and fetal tissues will be collected for histologic analysis and determination of ICA concentrations using existing ELISA’s and GC/MS methods. Proteomic analyses via LC/MS/MS techniques will be done. 1.3 Pen and field studies using cattle in high, medium and low body condition will be done to determine effects on needle consumption and grazing times. Nutrient supplements will be offered to determine if pine needle consumption will be altered. 2.1 The diterpene acid “fingerprint” of broom snakeweed from various populations in Arizona, New Mexico and Utah will be determined by chemical analysis. Subsequent in vitro and in vivo studies will be done to determine abortifacient activity. 2.2 A grazing study will be conducted to determine if various management practices can be implemented to force cattle to graze snakeweed as a biological control. A clipping study will be conducted to further describe the effects of defoliation on snakeweed and the surrounding plant community. 3.1 Alkaloids will be isolated by chemical methods and identified by chromatography, NMR, mass spectrometry, and elemental analysis. Toxicology will be evaluated using a mouse bioassay and cell lines that express nicotinic acetylcholine receptors. 3.2 A chemical fingerprint of Lupinus sulphureus collected from different locations will be generated using chemical methods. Fingerprints will be analyzed via cluster analysis and phylogenetic analysis will be performed using AFLPs (Amplified Fragment Length Polymorphisms) to determine the genetic relationship of the populations. 3.3 Pregnant goats in late gestation will be used to determine the rate of absorption, distribution and elimination of the teratogenic alkaloids. The pharmacokinetic profiles of the alkaloids will be compared between maternal and fetal systems. 3.4 Established transects will be monitored over the next 5 years to determine the influence of weather patterns on lupine density. Correlations of lupine age, class, density, and trends will be made with seasonal precipitation and temperature. 3.5 Consumption of lupines by cattle on rangelands dominated by low quality forages may be related to nutrient content. Twelve yearling heifers in a field study will be supplemented with different levels of protein to compare lupine ingestion. 3.6 Short-duration and high intensity grazing studies in early, mid, and late summer will be used to determine what role grazing pressure has on lupine intake during different seasons of the year. 4.1 A monogastric model (swine) will be used to determine the kinetics (clearance and metabolism) of a well known teratogenic alkaloid from Veratrum. This pilot project will be a model for testing the clearance of other plant toxins from animal tissues to evaluate food safety of animal products. Clearance rates between the monogastric model and small ruminant model will be compared.
3. Progress Report
Several herbicides were applied to snakeweed at Monticello and Nephi, UT in May and August 2008. Efficacy was evaluated in June 2009 and vegetation response and production was evaluated in 2010. Transects were read in 2009. Eight years of data were summarized and combined with WSU data and correlations were made with seasonal precipitation. Herbicides were evaluated for the control of broom snakeweed, one of the most ubiquitous range weeds in North America. Tordon was the most effective herbicide when applied in the spring and fall. Grazon, Milestone, and Escort were only acceptable when applied in the fall. The concentration of isocupressic acid, the abortifacient compound, in Ponderosa Pine was evaluated throughout the year and at different locations. Isocupressic acid concentrations were shown to vary between locations and between months at some locations. Lupine-infested rangelands are typically of poor nutritional quality during summer months when pregnant cattle most often consume the toxic lupine. Lupine, however, is a high nitrogen feed, and cattle may select lupine to meet their nutritional needs in late summer and during gestation. The consumption of lupine by cattle when supplemented with a high nitrogen feed was evaluated. In these studies the supplementation of nitrogen in the diet did not reduce lupine consumption by pregnant cattle. The influence of climate on population cycles of lupine was evaluated. Lupine populations increase in wet years and die off in drought.
1. Broom snakeweed is one of the most ubiquitous range weeds in North America. Herbicides were evaluated for its control in the 1970’s but new rangeland herbicides have been developed. ARS scientists at Logan, Utah, compared new herbicides with Tordon to evaluate their efficacy. Tordon was most effective when applied in either spring or fall, while Grazon, Milestone and Escort were acceptable when applied in fall. They also discovered that grass cover and production were greatest in Tordon plots, and were correlated with the degree of snakeweed control. These results were important for making informed recommendations for snakeweed control to ranchers and land managers.
2. Evaluate the influence of climate on population cycles of lupine. A catastrophic outbreak of crooked calves occurred in 1997 following 2 extremely wet years, and there appears to be correlation with increased lupine populations and wet years. Since 1996, extended drought conditions have caused most lupine populations to die out. Relationships discovered by ARS scientists at Logan, Utah between climatic patterns and lupine populations will enable ranchers and land managers to predict lupine outbreaks and take alternative management measures to avoid crooked calves.
3. Evaluate the concentrations of isocupressic acid (ICA) in Ponderosa Pines through the year. Ponderosa Pine (Pinus ponderosa) is distributed throughout the western half of North America, where it is the most widely adapted and ubiquitous conifer. Ponderosa Pine contains ICA, a diterpene acid, which has been shown to be responsible for its abortifacient activity. The objective of this study was to establish a sampling protocol for pine needles and to determine if ICA concentrations change as a function of the environment or if there is location-to-location variation in ICA content. ARS scientists at Logan, Utah established a sampling protocol for pine needles. They determined that ICA concentrations are not uniform throughout an individual tree. Consequently collecting a composite sample from a tree is most representative of a tree’s ICA content. Additionally, ICA concentrations were shown to vary between locations and between months at some locations. This work may explain partially why the incidence of pine needle abortion may be greater at certain locations. Furthermore, this work provides a foundation for further research to help understand how ICA concentrations vary between location and time, which may be used to help refine management recommendations.
4. Nitrogen supplementation of cattle grazing lupine-infested rangelands. Lupine infested rangelands are typically of poor nutritional quality during summer months when pregnant cattle most often consume the toxic lupine. Lupine, however, is a high nitrogen feed, and cattle may select lupine to meet their nutritional needs during gestation. ARS scientists at Logan, Utah evaluated the consumption of lupine by cattle when supplemented with a high N feed. Three replicates of two treatments (supplemented and not) were used in a grazing study in eastern Washington with 12 pregnant cows. Cattle grazed on a lupine-infested pasture for 3 weeks during 50-70 days of gestation. Cattle ate considerable lupine during the trials, but there were no differences between the treated and untreated animals. This research indicated that nitrogen supplement did not ameliorate lupine consumption by pregnant cattle. Findings from these studies will be transferred to cattle producers for eventual application in refining solutions to lupine poisoning in cattle.
5. Effects of teratogenic plants on early embryonic survival. ARS scientists at Logan, Utah treated pregnant Spanish goats with Nicotiana glauca during various stages of pregnancy (0.10; 10-20; 20-30 and 30-40) to evaluate the question, does lupine ingestion in cows during early gestation cause embryonic loss? Preliminary data, using a goat model suggests that these teratogenic alkaloids do not cause early embryonic loss nor do they cause birth defects when ingested during these early gestational periods. Results from this study will be implemented in grazing recommendations to reduce losses from lupine-induced crooked calf syndrome.
6. Intermittent feeding of teratogenic plants to goats. Intermittent grazing has been suggested as a possible management tool to mitigate the losses from lupine-induced crooked calf syndrome in the northwest. To test this hypothesis, ARS scientists at Logan, Utah fed pregnant Spanish goats the teratogenic plant Nicotiana glauca at intervals of 5 days on treatment and 2 days off from gestation days 30-60. Because the lupine-induced skeletal contractures and cleft palate result from alkaloid-induced fetal inactivity, the theory proposed was that 2 days off treatment would allow fetal movement to return, albeit for only 12-24 hours between treatment periods. Results of the study showed that even though fetal movement as observed with ultrasound did return during the rest periods this was not long enough to prevent the skeletal malformations or cleft palate. This information will be used by cattle producers in grazing strategies to reduce losses from lupine and to improve utilization of critical rangelands.
5. Significant Activities that Support Special Target Populations
Eastern Washington Cattlemen meeting 1 March 2010. 50 ranchers and land management agency personnel, Ritzville WA. Targeted to small farmers and ranchers. Ranchers will be able to predict lupine population outbreaks and manage cattle to reduce the risk of crooked calves.
Gardner, D.R., Panter, K.E., Stegelmeier, B.L. 2010. Implication of Agathic Acid from Utah Juniper Bark as an Abortifacient Compound in Cattle. Journal of Applied Toxicology, 30:115-119, 2010. DOI 10:1002/jat.1476