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Consumption of locoweeds, legumes endemic in arid western USA, has long been associated with locoism, a disease of ruminant animals. To explore the relationship between fungi associated with locoweed and locoweed toxicity, 11 locoweed populations from various sites in New Mexico were assessed for endophytic fungi. Endophytes were isolated from the leaves, stems, seeds, and flowers of eight populations of the toxic locoweeds Astragalus mollissimus, Oxytropis lambertii, and O. sericea. Fungal cultures grew very slowly and sporadically produced subcylindrical conidia with very dark transverse septa. All cultured endophytes produced the alkaloid swainsonine, which causes locoism. Endophyte-infected locoweed populations produced swainsonine, and the swainsonine level of endophyte strains in vitro was highly correlated with the swainsonine level of their host plant populations. The rDNA ITS from mycelia from four endophyte isolates and beta-tubulin encoding regions from mycelia of 18 fungal endophyte isolates were amplified using PCR and the nucleic acid sequences were analyzed. The nucleic acid sequences of the beta-tubulin encoding regions were essentially identical among all the endophytes regardless of plant genus and locations. Morphological evidence and sequence analysis of the ITS region suggest that the endophytes are most closely related to Embellisia. However, with the paucity of Embellisia species represented in sequence databases, precise taxonomic placement will await further study.

By herbological study and investigation, "Dekesha" used by Mongolia doctors mainly contains 17 species from 3 genus of 3 family, but "Dakesha" in Inner Mongolia Standard of Medicinal Materials only contains 2 species which are Oxytropis myriophylla and O. hirta.

Four new triterpene glycosides: one cycloartane-type glycoside and three azukisapogenol glycosides were isolated together with one known oleanene bisdesmoside from the Mongolian natural medicine, Oxytropis myriophylla.

The effects of ionophore supplementation on selected serum constituents of sheep consuming locoweed were investigated. Sixteen sheep were allotted by weight to a 2x2 factorial arrangement of treatments: 1) no locoweed, no lasalocid, 2) no locoweed, 0.75 mg lasalocid/kg BW, 3) 0.5 mg swainsonine/kg BW, no lasalocid, 4) 0.5 mg swainsonine/kg BW, 0.75 mg lasalocid/kg BW. Swainsonine was provided by locoweed (Oxytropissericea), and sheep were fed a blue grama based diet at 2.5% BW for a 35 d treatment period. Diets were formulated to be isocaloric and isonitrogenous. Blood samples were collected on d 1, 7,14, 21, 31 and 35 to determine serum swainsonine concentration, alkaline phosphatase, total iron, aspartate aminotransferase, g-glutamyltransferase, and lactate dehydrogenase activity and total cholesterol, and triglyceride concentrations. No lasalocid by locoweed interaction (P0.4) was noted for any response variable measured. Average daily gains (P = 0.4) and orts (P = 0.7) were not affected by the treatments. No lasalocid treatment (P = 0.7) or day (P = 0.1) effect of serum swainsonine was observed. A locoweed by day interaction (P0.0001) of serum alkaline phosphatase was detected. Alkaline phosphatase levels were elevated (P0.01) for locoweed treated sheep at 24 h following initial exposure and remained elevated throughout the trail. Total iron was suppressed (P0.08) in locoweed fed sheep. A day effect (P0.02) was observed for serum iron. However, no linear, quadratic, or cubic effects of day were noted (P0.2). A locoweed by day interaction (P0.0001) of serum aspartate aminotransferase and g-glutamyltransferase was detected. Aspartate aminotransferase levels were elevated (P0.0001) by d 7 for locoweed treated animals and remained elevated throughout the trial. g--Glutamyltransferase levels were suppressed (P0.0001) by day 7 for locoweed treated animals and remained suppressed throughout the trial. A locoweed by day interaction (P = 0.06) of serum cholesterol was detected. However, no linear, quadratic, or cubic effects of day were detected (P = 0.2). Lasalocid treatment had no effect on any serum constituent measured. Use of lasalocid in grazing animals should not increase the likelihood of locoweed intoxication.

The new alkaloid oxytriphine, the parent of natural 2-oxazoline derivatives, has been isolated from the epigeal part ofOxytropis trichophysa; and its structure has been established as (5S)-(+)-2,5-diphenyl-2-oxazoline. (-)-N-Benzoyl-2-phenyl-2-hydroxyethylamine and benzoic acid have been detected in this plant for the first time. A hypothesis of the possible biogenetic interrelationship of the compounds isolated is put forward.

Five aphid species collected on Wrangel Island (Russia) are presented. One species, Aphis polaris sp. nov., feeding on Astragalus alpinus L. and Oxytropis sp., is described, and the fundatrix morph of two others, Pterocomma groenlandicum Hille Ris Lambers, 1952 and Metopolophium sabihae Prior, 1976., is described for the first time.

The rangelands of China are an important resource for livestock production, and play a strategic role in maintaining ecosystems and protecting the living environment of humans. Drought, overgrazing, infrastructure development, insufficient investment and poor management of rangelands have led to the invasion and spread of poisonous weeds in these rangelands in recent years. The rapid spread of poisonous weeds over the last few decades have caused a series of ecological problems, including a decrease in biological diversity and consequent desertification, and they are seriously affecting the ecological balance of rangelands, and the sustainable livestock production. Locoweeds, which belong to the genera Oxytropis and Astragalus, are an important species of poisonous legumes in the western rangelands of China, causing large economic losses. This review summarises the species and their ecological distribution, the toxic ingredients, the poisoning mechanism of locoweeds and damage control techniques for locoweeds. It attempts to highlight certain issues relating to research on locoweeds and how they are being tackled in order to understand the significance of locoweeds in preserving ecosystem diversity and the steps that require to be taken to control the spread of locoweeds in the western natural rangeland of China.

Mesorhizobium sp. strain N33 ( Oxytropis arctobia ), a rhizobial strain isolated in arctic Canada, is able to fix nitrogen at very low temperatures in association with a few arctic legume species belonging to the genera Astragalus, Onobrychis , and Oxytropis . Using mass spectrometry and nuclear magnetic resonance spectroscopy, we have determined the structure of N33 Nod factors, which are major determinants of nodulation. They are pentameric lipochito-oligosaccharides 6-O sulfated at the reducing end and exhibit other original substitutions: 6-O acetylation of the glucosamine residue next to the nonreducing terminal glucosamine and N acylation of the nonreducing terminal glucosamine by methyl-branched acyl chains of the iso series, some of which are α,β unsaturated. These unusual substitutions may contribute to the peculiar host range of N33. Analysis of N33 whole-cell fatty acids indicated that synthesis of the methyl-branched fatty acids depended on the induction of bacteria by plant flavonoids, suggesting a specific role for these fatty acids in the signaling process between the plant and the bacteria. Synthesis of the methyl-branched α,β-unsaturated fatty acids required a functional nodE gene.

A new species Oxytropis sanjappae is described and illustrated from the Himalaya in India. The new species is widely scattered from Losar to Kaza in Lahul-Spiti region of Himachal Pradesh State. The relationship of the species has been discussed with O. cachemiriana and O. tatarica. The new species differs in having hairs very dense, silky and white, stems generally absent or quite reduced, racemes capitate, globose-ovoid or oblong, many-flowered, dense and elongating in infruitescence, calyx teeth distinctly longer than tube, corolla light purplish pink and almost equal to calyx, wing petals obtuse at apex, mucro of the keel petal ca. 1 mm long and pods comparatively larger in size. A taxonomic key to the all 18 species of the genus occurring in India including new ones has been provided for the first time. In addition, the ecological studies related with the frequency, density, basal cover and importance value index (IVI) have also been carried out to know the conservation status of the species in the Himalaya.

Three flavonoids and three saponins have been isolated from Oxytropis species. Their structures were determined as isorhamnetin-3-O-beta-D-glucoside, rhamnetin-3-O-beta-D-galactoside, apigenin, 3-O-[alpha-L-rhamnopyranosyl (1----2)-beta-D-glucopyranosyl(1----4)-beta-D-glucuronopyranosyl]+ ++soyasapogenol B, 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucuronopyranosyl] azukisapogenol and a new saponin 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucopyranosyl]-25-O-alpha-L- rhamnopyranosyl-(20S,24S)-3 beta,16 beta, 20,24,25-pentahydroxy-9,19-cycloanostane.

The pool of storage carbohydrates in plants may be formed in competition with allocation to growth (“true reserves”) or, where growth is inhibited by external factors, with no cost to growth (“accumulated reserves”). The latter hypothesis was addressed using Oxytropis sericea, a perennial herb from the Rocky Mountains. To generate variation in growth rate, greenhouse‐cultivated plants were assigned to low or high nutrient levels in 2 yr. Age of plants was also varied either by conducting consecutive harvests (1996) or using plants of different initial age (1997). In both years, plants from the high‐nutrient group attained larger vegetative biomass than plants in the low‐nutrient group and also displayed an overall lower carbon allocation to storage, consistent with the accumulation hypothesis.

A novel plant-induced lysosomal storage disease was observed in goats from a village in Mozambique. Affected animals were ataxic, with head tremors and nystagmus. Because of a lack of suitable feed, the animals consumed an exotic hedge plant growing in the village that was identified as Ipomoea carnea (shrubby morning glory, Convolvulaceae). The toxicosis was reproduced by feeding I. carnea plant material to goats. In acute cases, histologic changes in the brain and spinal cord comprised widespread cytoplasmic vacuolation of neurons and glial cells in association with axonal spheroid formation. Ultrastructurally, cytoplasmic storage vacuoles in neurons were membrane bound and consistent with lysosomes. Cytoplasmic vacuolation was also found in neurons in the submucosal and mesenteric plexuses in the small intestine, in renal tubular epithelial cells, and in macrophage-phagocytic cells in the spleen and lymph nodes in acute cases. Residual alterations in the brain in chronic cases revealed predominantly cerebellar lesions characterized by loss of Purkinje neurons and gliosis of the Purkinje cell layer. Analysis of I. carnea plant material by gas chromatography—mass spectrometry established the presence of the mannosidase inhibitor swainsonine and 2 glycosidase inhibitors, calystegine B2 and calystegine C1, consistent with a plant-induced α-mannosidosis in the goats. The described storage disorder is analogous to the lysosomal storage diseases induced by ingestion of locoweeds ( Astragalus and Oxytropis) and poison peas ( Swainsona).

Locoweed poisoning is seen throughout the world and annually costs the livestock industry millions of dollars. Swainsonine inhibits lysosomal alpha-mannosidase and Golgi mannosidase II. Poisoned animals are lethargic, anorexic, emaciated, and have neurologic signs that range from subtle apprehension to seizures. Swainsonine is water-soluble, rapidly absorbed, and likely to be widely distributed in the tissues of poisoned animals. The purpose of this study was to quantify swainsonine in tissues of locoweed-poisoned sheep and determine the rate of swainsonine clearance from animal tissues. Twenty-four crossbred wethers were gavaged with ground Oxytropis sericea to obtain swainsonine doses of 1 mg swainsonine x kg(-1) BW x d(-1) for 30 d. After dosing, the sheep were killed on d 0, 1, 2, 3, 4, 6, 14, 30, 60, and 160. Animal weights and feed consumption were monitored. Serum was collected during dosing and withdrawal periods, and tissues were collected at necropsy. Serum swainsonine concentrations were determined using an alpha-mannosidase inhibition assay. Swainsonine concentrations in skeletal muscle, heart, brain, and serum were similar at approximately 250 ng/g. Clearance from these tissues was also similar, with half-lives (T(1/2)) of less than 20 h. Swainsonine at more than 2,000 ng/g, was detected in the liver, spleen, kidney, and pancreas. Clearance from liver, kidney, and pancreas was about T(1/2) 60 h. These findings imply that poisoned sheep have significant tissue swainsonine concentrations and animals exposed to locoweed should be withheld from slaughter for at least 25 d (10 T(1/2)) to ensure that the locoweed toxin has cleared from animal tissues and products.

The legume genera Astragalus and Oxytropis belong to the tribe Galegae. These legumes are common in Arctic and Temperate climatic zones. Previous studies based on cross-inoculation experiments and numerical taxonomy (Prevost et al., 1987; Novikova et al., 1993; 1994) suggested that the rhizobia associated with these legumes were closely related. Also the legume species Onobrychis viciifolia (sainfoin, tribe Hedysareae) was effectively nodulated by rhizobia isolated from Astragalus and Oxytropis spp. (Prevost et al., 1987). Rhizobia isolated from A. sinicus were classified in a new species, Mesorhizobium huakuii, (Chen et al., 1991; Jarvis et al., 1997). Other rhizobia from Astragalus and Oxytropis spp. appeared phenotypically (Novikova et al., 1993) or phylogenetically (Oyaizu et al., 1992) related with M. loti.

The genetic diversity of 44 rhizobial isolates from Astragalus, Oxytropis, and Onobrychis spp. originating from different geographic locations was evaluated by mapped restriction site polymorphism (MRSP) analysis of 16S rRNA genes and by PCR DNA fingerprinting with repetitive sequences (REP-PCR). A comparison of tree topologies of reference strains constructed with data obtained by MRSP and by 16S rRNA gene sequence analyses showed that the topologies were in good agreement, indicating that the MSRP approach results in reasonable estimates of rhizobial phylogeny. The isolates were distributed into 14 distinct 16S rRNA gene types clustering into three major groups which corresponded with three of the genera within the legume symbionts. Most of the isolates were within the genus Mesorhizobium. Five were identified with different genomic species nodulating Lotus spp. and Cicer arietinum. Three Astragalus isolates were classified as Bradyrhizobium, one being similar to Bradyrhizobium elkanii and another being similar to Bradyrhizobium japonicum. Six of the isolates were related to species within the genus Rhizobium. Two were similar to Rhizobium leguminosarum, and the remainder were identified as Rhizobium gallicum. DNA fingerprinting by REP-PCR revealed a high level of diversity within single 16S ribosomal DNA types. The 44 isolates were distributed into 34 REP groups. Rhizobial classification at the genus and probably also the species levels was independent of geographic origin and host plant affinity.

Locoweeds ( Oxytropis and Astragalus spp.) are toxic plants found on many rangelands. Preferences for locoweed are learned ; livestock often initially reject the plant, but learn to eat locoweed after continued exposure. Maternal influences are important in shaping diet selection in young animals. We studied the influence of ewe consumption of locoweed on lamb selection of the plant. Twenty-four ewes were divided into three treatment groups (n = 8) : 1) ewes conditioned to eat locoweed (Oxytropis sericea) and avoid sodgrass (Poa pratensis) (Loco+Sod-) ; 2) ewes conditioned to avoid locoweed and eat sodgrass (Loco-Sod+) ; and 3) ewes conditioned to eat sodgrass and not exposed to locoweed (Loco0Sod+). A control group (n = 8) was composed of orphan lambs with no maternal influence (Orphans). All ewes were exposed to locoweed and(or) sodgrass without their lambs for 1 wk. Lambs were exposed to either locoweed or sodgrass with ewes for 5 min/d for 6 d. After weaning, lambs were tested for preferences by offering both locoweed and sodgrass for 3 min/d for 5 d ; lambs were then offered only locoweed for 5 min/d for 5 d. Sodgrass was preferred by lambs. Lambs in the Loco+Sod- treatment group tended (P =.06) to take more bites of locoweed than lambs in the Loco0Sod+ group. Also, lambs in the Loco0Sod+ and Loco-Sod+ groups tended (P =.07) to take fewer locoweed bites compared with Orphans. Even though these results tended towards significance, the magnitude of the effect was small. There were no treatment effects when locoweed was offered alone. Although exposure with the mother did not strongly influence lambs to eat (or avoid) locoweed, all lambs ate some locoweed during testing. Short-term maternal influence does not seem to be sufficient to condition a preference for locoweed in lambs.

Desertification and degradation of pastures has occurred over the last 50 years on the western grasslands of China due to human factors including overgrazing, unsuccessful reclamation of land, loss of soil through inappropriate cultivation, mining, population growth, and natural factors including drought. This has led to a decrease in herbage mass and a reduction in carrying capacity, leading to a reduction in the sustainability of livestock systems. One of the effects of desertification and degradation has been an increase in the area of poisonous plants over this period and these plants now cover 20.5 m ha and are now a contributing factor and symptom of the degeneration of the grasslands. The main poisonous plants that threaten livestock production are locoweeds (Oxytropis and Astragalus species), Stellera chamaejasme, Achnaterum inebrian, Cynanchum komarovii and Aconitum carmichaeli. Based on an analysis of previous and current data, this review describes the distribution of these poisonous plants and their impact on livestock production and assesses the state of poisonous plants in the western grasslands are having on the sustainability of livestock production, and addresses the issues of integrated control measures and the development of appropriate livestock management systems that could be implemented.

Dickore, W. B. & Kriechbaum, M.: Oxytropis iridum (Leguminosae), a new species from SE Tibet (Xizang, China), including phytogeographical notes. — Willdenowia 36: 857–865.-ISSN 0511-9618; © 2006 BGBM Berlin-Dahlem. doi:10.3372/wi.36.36216 (available via http://dx.doi.org/) Oxytropis iridum is described as a species new to science from the Inner E Himalaya of the Xizang Autonomous Region. The new species is well defined by its morphological traits, geographical distribution and habitat preferences and belongs to the largest and probably most controversial, typical subgenus of Oxytropis. It is apparently most closely related to the circumarctic O. deflexa (Tibet, N Asia, W North America) and to the W Himalayan endemic O. mollis.

The name Oxytropis xinglongshanica C. W. Chang was not validly published in 1987 because two types were indicated. The name is validated here.

In recent years livestock death losses from poisonous plants in the western United States have averaged about 2-3% annually. A review of 36 grazing studies in North America shows poisonous plant availability and death losses of livestock from poisonous plants are closely associated with grazing intensity. Across studies, livestock death losses to poisonous plants average about 2.0% under moderate grazing compared with 4.8% under heavy grazing intensities. Sheep and goat losses from poisonous plants appear to be increased more by heavy stocking than those from cattle. Impacts of poisonous plants on livestock reproductive success are difficult to quantify, but probably reduce calf and lamb crops, even when grazing intensities are conservative. Increased poisonous plant consumption may explain in part why calf and lamb crops average about 7% lower under heavy compared to moderate grazing. With the exception of 1 Texas study, rotation and continuous/season long grazing systems show little differences in livestock death losses under comparable stocking rates. Certain plants, such as locoweeds (Astragalus sp.) and larkspur (Delphinium sp.), can elevate livestock death losses, even when grazing intensities are moderate or conservative. Special management programs that involve careful timing of grazing, aversive conditioning, and creation of locoweed (or larkspur)-free pastures can reduce problems with these plants. Use of adapted livestock is a critical part of minimizing poisonous plant problems. However, on some rangelands, such as those with infestations of locoweed and larkspurs, naive livestock may be less affected by poisonous plants than familiar livestock. Knowledge of poisonous plant identification, conditions of toxicity, and affects on the animal, in conjunction with conservative grazing, will in most cases avoid excessive death and productivity losses from poisonous plants. In some cases livestock can be conditioned or trained to not consume poisonous plants. It can be concluded that most livestock losses from poisonous plants are caused by poor management. DOI:10.2458/azu_jrm_v55i3_holechek

In the past, excessive numbers of livestock on western U.S. rangelands, reoccurring droughts, and lack of management resulted in retrogression of plant communities. Poisonous plants and other less palatable species increased with declining range condition and livestock were forced to eat these poisonous species because of a shortage of desirable forage, resulting in large, catastrophic losses. The level of management on most western rangelands has improved during the last 60 years, resulting in marked improvement in range condition; yet losses to poisonous plants still occur, though not as large and catastrophic as in the past. Some poisonous species are major components of the pristine, pre-European plant communities [tall larkspur (Delphinium barbeyi Huth), Veratrum californicum Durand, water hemlock (Cicuta douglasii (DC.)Coult. &Rose), bracken fern (Pteridium aquilinum (L.) Kuhn), chokecherry (Prunus virginiana L.), Ponderosa pine (Pinus ponderosa Lawson), and various oak species (Quercus spp.)]. Although populations of many poisonous seral increaser species have declined with better management, they are still components of plant communities and fluctuate with changing precipitation patterns [locoweed (Astragalus and Oxytropis spp.), lupine (Lupinus spp.), death camas (Zigadenus spp.), snakeweed (Gutierrezia spp.), threadleaf groundsel (Senecio longolobis Benth.), low larkspur (Delphinium nuttallianum Pritz.), timber milkvetch (Astragalus miser Dougl. ex Hook.), redstem peavine (A. emoryanus (Rydb.) Cory), western bitterweed (Hymenoxys odorata D.C.), orange sneezeweed (Helenium hoopesii Gray), twin leaf senna (Cassia roemeriana Schelle), and white snakeroot (Eupatorium rugosum Houtt)]. Many of the alien invader species are poisonous: [Halogeton glomeratus (Bieb.) C.A. Mey, St. Johnswort (Hypericum perforatum L.), poison hemlock (Conium maculatum L.), tansy ragwort (Senecio jacobaea L.), hounds tongue (Cynoglossum officinale L.), leafy spurge (Euphorbia esula L.), yellow star thistle (Centaurea solstitialis L.) and other knapweeds (Centaurea spp.)]. Poisoning occurs when livestock consume these plants because they are either relatively more palatable than the associated forage, or from management mistakes of running short of desirable forage. DOI:10.2458/azu_jrm_v55i3_ralphs

Poisonous plants that impair normal reproductive functions in livestock include Veratrum californicum Durand, lupines, ponderosa pine (Pinus ponderosa Dougl.), broom snakeweed (Gutierrezia sarothrae (Pursh) Britt. R (2) know what poisonous plants grow on ranges and understand their effects; (3) develop a management plan to provide for alternate grazing in poisonous plant-free pastures during critical times; (4) provide for balanced nutrition, including protein, energy, minerals and vitamins; (5) maintain a good herd health program; (6) integrate an herbicide treatment program to reduce poisonous plant populations or to maintain clean pastures for alternate grazing; and, (7) manage the range for maximum forage production. DOI:10.2458/azu_jrm_v55i3_panter

A new species of Oxytropis (Leguminosae) from Xizang (Tibet) in China, 0. qamdoensis X. Y. Zhu, Y. F. Du & H. Ohashi, is described and illustrated. The new species is very similar to 0. ochrantha (sect. Baicalia Steller ex Bunge) and shares with it verticillate and opposite leaflets and glandular hairs, but differs in having leaflets with 9-11 whorls per leaf, the standard bilobed at the apex, wings emarginate at the apex, the beak of the keel-petals 1.0-1.5 mm long, and pods with whitetinged hairs.

A series of experiments were conducted to investigate the elimination of swainsonine in the milk of lactating ruminants following a single dose oral exposure to swainsonine (locoweed; Oxytropis sericea) and to assess subsequent subclinical effects on the mothers and their nursing young. In a preliminary experiment, lactating ewes were gavaged with locoweed providing 0.8 mg swainsonine/kg BW (n = 4; BW = 75.8 +/- 3.6 kg; lactation = d 45) and lactating cows were offered up to 2.0 mg swainsonine/kg BW free choice (n = 16; BW = 389.6 +/- 20.9 kg; lactation = d 90). Serum and milk were collected at h 0 (before treatment), 3, 6, 12, and 24 for ewes, and h 0 (before treatment), 6, 12, 18, and 24 for cows. Swainsonine was highest (P0.05) by h 6 in the serum and milk of ewes. Consumption of at least 0.61 mg swainsonine/kg BW induced consistent (0.025 microg/mL) appearance of swainsonine in cow serum and milk. In response to the results obtained in the preliminary experiment, a subsequent experiment utilizing lactating ewes (n = 13; BW = 74.8 +/- 6.4 kg; lactation = d 30) and cows (n = 13; BW = 460.8 +/- 51.9 kg; lactation = d 90) was conducted. Each lactating ruminant was gavaged with a locoweed extract to provide 0 (control), 0.2, or 0.8 mg swainsonine/kg BW and individually penned with her nursing young. Serum and milk from the mothers and serum from the nursing young were collected at h 0 (before treatment), 3, 6, 9, 12, 24 and 48 (an additional sample was obtained at h 72 for ewes and lambs). Serum and milk swainsonine was higher (P0.05) in the 0.8 mg treated groups and maximal (P0.05) concentrations occurred from h 3 to 6 for ewes and h 6 to 12 h for cows (P0.05). Rises in alkaline phosphatase activity indicated subclinical toxicity in the treated ewes (P0.05). Following a single dose oral exposure to 0.2 and 0.8 mg swainsonine/kg BW provided by a locoweed extract, swainsonine was detected in the serum and milk of lactating ewes and cows, and rises in serum alkaline phosphatase activity were observed in the ewes. Neither swainsonine nor changes in alkaline phosphatase activity was detected in the serum of the lambs and calves nursing the ewes and cows dosed with swainsonine.

Alkaloids constitute the largest class of plant secondary compounds, occurring in 20 to 30% of perennial herbaceous species in North America. Alkaloid-containing plants are of interest, first because alkaloids often have pronounced physiological reactions when ingested by livestock, and second because alkaloids have distinctive taste characteristics. Thus, alkaloids may kill, injure, or reduce productivity of livestock, and have the potential to directly or indirectly alter diet selection. We review 7 major categories of toxic alkaloids, including pyrrolizidine (e.g., Senecio), quinolizidine (e.g., Lupinus), indolizidine (e.g., Astragalus), diterpenoid (e.g., Delphinium), piperidine (e.g., Conium), pyridine (e.g., Nicotiana), and steroidal (Veratrum-type) alkaloids. Clinically, effects on animal production vary from minimal feed refusal to abortion, birth defects, wasting diseases, agalactia, and death. There are marked species differences in reactions to alkaloids. This has been attributed to rumen metabolism, alkaloid absorption, metabolism, excretion or directly related to their affinity to target tissues such as binding at receptor sites. In spite of alkaloids reputed bitter taste to livestock, some alkaloid-containing plant genera (e.g., Delphinium, Veratrum, Astragalus, Oxytropis, and Lupinus) are often readily ingested by livestock. Management schemes to prevent losses are usually based on recognizing the particular toxic plant, knowing the mechanism of toxicity, and understanding the temporal dynamics of plant alkaloid concentration and consumption by livestock. Once these aforementioned aspects are understood, losses may be reduced by maintaining optimal forage conditions, adjusting grazing pressure and timing of grazing, aversive conditioning, strategic supplementation, changing livestock species, and herbicidal control. DOI:10.2458/azu_jrm_v54i4_pfister

Plants of the genus Oxytropis (fam. Fabiaceae) are widely used in Tibetan and Mongolian folk medicine. Oxytropis muricata Pall. and O. trichophysa Bge. are employed in diseases of the liver and in the treatment of wounds and of skin diseases [i]. In the present communication we give the results of a study of the flavonoids of the epigeal parts of the abovementioned plants gathered in the vegetation period on Mongolian territory.

Livestock producers and others knowledgeable about the locoweed problem in northeastern New Mexico were surveyed to obtain the production information needed to estimate economic losses from locoweed (Oxytropis/Astragalus) poisoning. A partial budgeting approach was used to estimate economic losses based on animal performance differences with increasing levels of poisoning. With current production costs and 1990-96 average beef prices, annual locoweed poisoning losses were estimated to be $75 head-1 for moderately poisoned animals, and $282 head-1 for severely poisoned animals. The most common locoweed management strategy used by northeastern New Mexico ranchers was to move animals observed eating locoweed into locoweed-free areas. Rehabilitation of these animals for an extended period before sale was found to decrease economic loss relative to immediate sale. Moderately and severely poisoned animals that are rehabilitated were estimated to gain 14% and 29% less than non-intoxicated animals. Other management options including chemical locoweed control, fencing, and locoweed aversion were found to be economically justified when relatively high locoweed infestations are anticipated. DOI:10.2458/azu_jrm_v53i4_torell

The objective of this study was to determine if cattle that were familiar with white locoweed (Oxytropis sericea Nutt, ex T&G) could be aversively conditioned to avoid eating it. In the first preliminary trial, we tried to aversely condition native steers that were already eating locoweed. Six of 12 steers were penned, fed fresh-picked locoweed, then dosed via a stomach tube with lithium chloride (LiCl, 200 mg/kg BW). When released into the locoweed-infested pasture, they gradually increased locoweed consumption over the next 5 days. The conditioning procedure was repeated with a lower dose (100 mg/kg BW), but locoweed consumption increased within 10 days until they were consuming as much as the non-averted controls. In the second trial, we compared the strength and longevity of aversion between steers that were familiar with locoweed (n = 6) and naive steers (n = 6). Both groups were averted to locoweed as described in Trial 1 and returned to locoweed-infested pasture. The Familiar group decreased locoweed consumption for the first 2 days, then gradually increased locoweed consumption and extinguished the aversion. The Naive group subsequently refused to graze locoweed. In the third trial, aversions were reinforced following grazing locoweed in the pasture. Three steers from the Familiar group were allowed to graze locoweed for 30 min. periods, then were returned to the pen and dosed with LiCl (100 mg/kg BW). These steers were kept in the pen and allowed to recover for 36 hours. This reinforcement process following grazing was repeated 4 times. Steers in the Reinforced group abstained from eating locoweed when released into the locoweed-infested pasture for the remainder of the trial. Reinforcement of aversions following field grazing of locoweed prevented cattle that were familiar with locoweed from grazing it.

Sixteen ram lambs (5 mo old, average BW = 49 +/- 1.4 kg) received a control diet (50% concentrate, 13.1% CP) or a diet containing 7, 14, or 21% locoweed (LW, DM basis). Rams were housed in individual pens (2.5 x 3.5 m) in an enclosed facility (14 h light, 10 h dark) with free access to feed and water. After 35 d of LW feeding, rams fed the 21% LW diet ate 1.3 to 1.6 kg/d, whereas rams fed the other three diets ate 1.6 to 2.0 kg/d. On d 35, BW (mean +/- SE) were 58.3, 57.2, 57.2, and 55.4 (+/- 1.5 kg/d) for ram lambs receiving 0, 7, 14, and 21% LW, respectively (P.20). An inverse relationship for BW (P.10) and gain (P = .04) was observed 1 mo after LW feeding ended relative to amount of LW in the diet. Serum alkaline phosphatase increased with increasing LW (P.05), and thyroxine concentration was decreased (P.05) by LW ingestion. On d 35, serum LH averaged 6.8, 9.9, 11.6, and 9.9 (+/- 1.8) ng/mL (P = .56), whereas testosterone averaged 3.5, 2.6, 3.0, and 1.6 (+/- .5) ng/mL (linear effect of LW, P = .05) over a 5-h period after GnRH injection (i.m., 50 microg) in lambs fed 0, 7, 14, and 21% locoweed, respectively. Semen volume, sperm motility, sperm cell concentration, and percentage of abnormal cells did not differ (P.50) on d 35. One month after the end of LW feeding, a linear (P = .06) decrease in sperm motility and scrotal circumference was observed relative to percentage of prior dietary LW. These data suggest that LW exerts adverse effects on the testes of young rams that may not be evident until several weeks after LW consumption ends.

Five sheep were fed a 10% locoweed (Oxytropis sericea) pellet or alfalfa pellets for 3- to 5-wk periods to determine the effects of intermittent locoweed ingestion on operant responding; three controls were fed alfalfa pellets for 22 wk. Sheep were trained to respond to a multiple schedule with a fixed ratio (FR) 5 and fixed interval (FI) 50 s as major elements; performance was reinforced with rolled barley. Locoweed-treated sheep decreased (P.05) FR response rate after 4 wk of locoweed feeding, but this decrease first appeared during the first recovery period (wk 6). The FR response rate of intoxicated sheep did not return to baseline during the remainder of the study and differed from controls during most of the study. Controls did not deviate (P.05) from their FR baseline except during wk 2. Sheep did not stabilize on the FI component. As locoweed-treated sheep became progressively more intoxicated, they altered their pattern of FR responses, with longer post-reinforcement pauses, and a slower overall FR rate. Intoxicated sheep ingested an average of .21 mg swainsonine.kg-1.d-1. Overt signs of intoxication were noted when two sheep were stressed on wk 17. These two sheep had neuroviseral vacuolation typical of locoweed poisoning, whereas the three remaining locoweed-treated sheep that were euthanatized 5 wk later showed little histologic evidence of intoxication. Our findings indicate that "on-off" or cyclic grazing of locoweed ranges should be approached cautiously. Such a grazing program may be feasible because of the rapid resolution of histologic pathology; however, an initial toxic insult of 4 wk seems to be excessive, even at low doses, because sheep may exhibit persistent behavioral abnormalities that require6 wk to resolve.

The effect of muskox herbivory on growth and reproduction in Oxytropis viscida was examined on Banks Island, N.W.T, during three growth seasons. Two levels of grazing were recognized. "Chomping," which occurs primarily early in the season, affects shoot tips and may include removal of all aboveground biomass. Chomping does not affect survival, but reduces plant diameter and probability of flowering for at least 2 yr following grazing. It also decreases the number of shoot tips during the year of grazing, and decreases the number of inflorescences for at least 1 yr following grazing. Chomping results in a change in plant morphology, including more tightly clustered growth tips and greener, more viscid leaves. Chomped plants are less likely to be grazed again in the year following herbivory. "Nibbling" refers to the selective removal of inflorescences and seed pods. Nibbling does not affect plant survival, shoot tip number, or number of inflorescences, but does decrease diameter for at least 1 yr following grazing. Results suggest that 0. viscida may not be continually defended and that resistance is induced by chomping but not nibbling. The strategy of this arctic herbaceous dicotyledon appears to be intermediate between that of arctic graminoids which exhibit rapid regrowth and that of slower growing, highly defended arctic shrubs.

Paper presented at the "Symposium on Ingestion of Poisonous Plants by Livestock," February 15, 1990, Reno, Nevada.