我国西部草原疯草的危害及其动物中毒病的控制

疯草是目前危害我国西部草原畜牧业可持续发展的严重毒草,给畜牧业造成严重的经济损失。本文从疯草的种类、分布、危害、有毒成分、中毒机理、临床症状以及中毒病的控制等方面进行了简要综述,并对疯草类植物资源的应用前景作了展望。     

西藏草原疯草分布、危害及其防治

疯草对西藏畜牧业的可持续发展以及草原的生态环境造成了严重威胁。本文从西藏草原疯草的种类、分布、对草原和畜牧业的危害、疯草毒性成分和中毒机理等方面进行简要综述,并提出了一些综合防治的建议。     

疯草类植物在美国天然草地的分布及其动物中毒病研究现状与展望

疯草专门指含苦马豆素、采食后引起慢性神经机能障碍、表现发疯样症状的一类毒草,由此所致中毒称为疯草病,主要分布在美国西部。近年来我国疯草面积不断增大,危害程度超过雪灾和疫病,已经成为危害我国西部草原畜牧业可持续发展的严重毒草。美国从19世纪末就开始疯草生物学、生态学、毒理学及其动物中毒病研究,是世界上率先开展疯草研究的国家,在应对草地疯草灾害防控方面具有丰富经验。我国天然草地疯草研究起步晚,与美国有很大差距。本文就美国天然草地疯草的研究历史、种类分布、灾害状况、毒理学和疯草防治技术等方面的进展进行归纳总结,旨在为我国天然草地疯草中毒病的致病机制和灾害防控技术研究提供借鉴。     

西藏草原疯草分布、危害及其防治

疯草对西藏畜牧业的可持续发展以及草原的生态环境造成了严重威胁。本文从西藏草原疯草的种类、分布、对草原和畜牧业的危害、疯草毒性成分和中毒机理等方面进行简要综述，并提出了一些综合防治的建议。     

疯草研究现状

中国疯草主要分布在西北、西南和华北广大牧区，面积已达400多万hm^2，严重威胁着当地畜牧业的发展，已造成巨大的经济损失。从疯草的分类和分布、危害、毒理学机制、中毒症状及病理变化、中毒的诊断与治疗、防除和综合利用研究7个方面，对疯草进行了综述。     

我国西部草原疯草危害调查

采用现场调查和资料收集相结合的方法,对我国疯草的种类、分布、危害及各地在疯草中毒防治方面的对策进行了调查研究.调查结果表明,我国有疯草44种(其中棘豆属23种,黄芪属21种),构成严重危害的有18种,分布面积超过1100万hm2,给草地畜牧业生产造成极大危害.并就其防治提出几点体会与建议.     

我国西部草原疯草危害调查

采用现场调查和资料收集相结合的方法。对我国疯草的种类、分布、危害及各地在疯草中毒防治方面的对策进行了调查研究。调查结果表明，我国有疯草44种（其中棘豆属23种。黄芪属21种），构成严重危害的有18种，分布面积超过1100万hm^2，给草地畜牧业生产造成极大危害。并就其防治提出几点体会与建议。     

疯草中毒防治研究进展

疯草(locoweed)包括棘豆属(Oxytropis sp.)和黄芪属(Astragalus L.)若干有毒植物,是目前世界范围内危害草原畜牧业可持续发展最严重的毒草。近年来,国内外关于疯草中毒的研究较多,主要集中在疯草有毒成分、动物疯草中毒机理、疯草中毒预防等的研究方面。在疯草中毒预防方面,先后采用了人工挖除、放火焚烧、化学药剂灭除等,这些方法在一定程度上发挥了作用,但从保护草原生态角度来看上述方法并不可行。疯草具有抗旱、抗寒、繁殖力强、分布密度大、营养价值高等特点,是特定草原生态群落的重要组成部分,也是重要的牧草资源。现将疯草中毒防治…     

苦马豆素对母畜繁殖机能的影响及防控

苦马豆素主要存在于豆科棘豆属和黄芪属植物如疯草中,动物采食大量疯草会发生神经中枢紊乱,苦马豆素中毒的母畜表现不孕、流产,产死胎、畸胎等,引起繁殖能力下降,妨碍家畜繁育和品种优化,给我国草原畜牧业造成严重的经济损失,严重制约了我国西部草原牧区养殖业的持续发展。现通过对疯草主要毒性成分苦马豆素对母畜的繁殖性能指标、生殖器官组织形态学病理变化和生殖激素的影响进行综述,旨在为母畜疯草中毒引起的繁殖机能紊乱疾病提供治疗及预防思路,降低牧区养殖业经济损失,提高我国畜牧业长远发展的能力。     

苦马豆素-BSA接种山羊的免疫学研究

疯草（Locoweed）是世界范围内危害草原畜牧业生产最严重的一类毒草，在我国主要分布于西部的广大草原，危害面积达1100万hm^2，并且日趋蔓延。动物采食疯草后不仅引起大量中毒死亡，更为重要的是导致母畜流产、不孕、胎儿畸形和公畜不育，同时疯草蔓延可促使草场退化，降低草场利用率，给草原畜牧业造成巨大的经济损失。国内外学者自1873年至今对动物疯草中毒做了大量的研究，现已确认的疯草毒素为吲哚兹啶生物碱-苦马豆素（swainsonine，SW）。疯草除含有毒素外，营养学研究也发现，其粗蛋白含量高达11％～12％，有着被作为优良饲草的潜力。     

疯草内生真菌研究进展

疯草含有疯草毒素,动物采食后能引起以慢性神经机能紊乱为特征的中毒病,是世界范围内危害草原畜牧业最严重的毒草之一.对疯草主要有毒成分苦马豆素来源问题的研究发现,疯草内生真菌与苦马豆素之间具有极为密切的关系.近年来,科研工作者对多种疯草的内生真菌进行分离,并对其与疯草的相互关系进行了深入研究.论文主要介绍了近年来国内外有关...     

内蒙古疯草及其研究进展

对内蒙古的疯草分布概况、牲畜疯草中毒机理、中毒的生态环境因素及其危害和疯草的开发利用进行了综述。     

内蒙古阿拉善盟草原疯草危害调查

采用现场调查和资料收集相结合的方法，对内蒙古阿拉善盟的阿拉善左旗、阿拉善右旗和额济纳旗3个旗疯草的种类、分布、危害及防治对策进行了调查研究。结果表明：阿拉善盟有疯草7种，其中棘豆属有毒植物3种，黄芪属有毒植物4种，分布面积超过139．33万hm^2，危害最严重的是小花棘豆和变异黄芪，给当地畜牧业造成了极大的危害，并就如何综合利用疯草提出了几点措施。     

疯草内生真菌研究现状与存在问题

疯草是世界范围内危害草原畜牧业可持续发展最严重的毒草。引起家畜疯草中毒的主要成分是吲哚里西啶生物碱--苦马豆素,苦马豆素除具有毒性外,还具有显著的抗菌、抗病毒、抗肿瘤、增强免疫等药理活性,有关苦马豆素产生机制、毒理和药理活性研究已成为人们研究的热点。为了揭示疯草毒性物质产生机制、疯草内生真菌与疯草抗逆性,特别是疯草毒性物质与疯草内生真菌互作关系等诸多问题,国内外科技工作者从20世纪末就开始致力于疯草内生真菌生物多样性、疯草内生真菌与苦马豆素产生关系以及与疯草抗逆性形成机制研究,已从多种疯草中分离到可产苦马豆素的内生真菌,并发现疯草内生真菌与疯草之间存在密切关系。本文对近年来国内外疯草内生真菌研究的主要内容及研究现状进行综述,并对该研究领域中存在的若干问题进行了探讨。     

The toxicosis of Embellisia fungi from locoweed (Oxytropis lambertii) is similar to locoweed toxicosis in rats

Locoweeds cause significant livestock poisoning and economic loss in the western United States. The toxicity of Embellisia sp. fungi isolated from locoweed was compared with locoweed toxicity using the rat as a model. Rats were fed diets containing locoweed, fungus and alfalfa, or alfalfa. Locoweed- and fungus-fed rats consumed swainsonine-containing food at approximately 1.3 mg x kg(-1) x d(-1), gained less weight (P = 0.001) and ate less than controls. Swainsonine is the principal agent responsible for inducing locoism in animals. The concentrations of alkaline phosphatase and aspartate aminotransferase enzymes were greater (P < 0.05) in serum of locoweed- and fungus-fed rats compared with control rats. Similar intracellular vacuolation was observed in renal, pancreatic, and hepatic tissues of rats that consumed either locoweed or fungus. Rats that ate locoweed or Embellisia fungi displayed indistinguishable toxicity symptoms. The Embellisia fungi from locoweed can induce toxicity without the plants. Locoism management strategies need to involve management of the Embellisia fungi.     

Effect of repeated locoweed feeding on peripheral lymphocytic function and plasma proteins in sheep

Seven healthy, adult, crossbred yearling ewes were given (orally) 340 g of locoweed (Astragalus lentiginosus) every day for 10 weeks. Another 7 ewes were not fed the plant, but were housed similarly (controls). Blood samples were obtained once a week to evaluate the mitogen-induced lymphocytic responsiveness. For the locoweed-exposed ewes, there was decreased activity in the presence of phytohemagglutinin (a T-cell mitogen). This effect, although not statistically significant at all times, was consistent and became significant after 7 weeks. A similar response was observed in the blood cell cultures in the presence of pokeweed mitogen, but the differences were not statistically significant at most time points. For the locoweed-exposed ewes there also were gradual numerical decreases in total leukocyte and lymphocytes in peripheral blood. Peripheral leukocytes had cytoplasmic vacuolation. The results indicated that a selective effect may occur on cell-mediated immune responses. Serum proteins and gamma-globulins were not affected by locoweed treatment. Locoweed, certain species of Astragalus and Oxytropis, causes considerable economic loss to the livestock industry of western United States. Locoweed consumption by livestock can result in neurologic problems, emaciation, habituation, and reproductive alterations. The reproductive alterations include abortions, birth defects, and some interference with spermatogenesis and oogenesis. Signs of poisoning are CNS depression, rough dry coat, dull eyes, irregular gait, and excitement when stressed. The microscopic lesions are neurovisceral cytoplasmic vacuolations. Microscopic lesions are also observed in the fetuses and newborns of dams which were fed locoweed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of previous locoweed (Astragalus and Oxytropis species) intoxication on conditioned taste aversions in horses and sheep

Locoweed species (Astragalus and Oxytropis spp.) are a serious toxic plant problem for grazing livestock. Horses and sheep have been conditioned to avoid eating locoweed using the aversive agent LiCl. The objective of this study was to determine if previous locoweed intoxication affects food aversion learning in horses and sheep. Horses and sheep were divided into 3 treatment groups: control (not fed locoweed and not averted to a novel feed); locoweed-novel feed averted (fed locoweed and averted to a novel feed); and averted (not fed locoweed and averted to a novel feed). Animals in the locoweed-novel feed averted groups were fed locoweed during 2 periods of 21 and 14 d, respectively, with each feeding period followed by a 14-d recovery period. Animals were averted to a novel test feed at the end of the first locoweed-feeding period, and periodically evaluated for the strength and persistence of the aversion. During the first recovery period, locoweed-novel feed averted horses ate less (9.5% of amount offered) of the test feed than did control horses (99.8%) and did not generally differ from averted horses (0%). During recovery period 2, locoweed-novel feed averted horses (4.3%) differed (P = 0.001) in consumption (% of offered) of the test feed from controls (100%) and the averted group (0%). Locoweed-novel feed averted sheep differed (P = 0.001) from controls (14.4 vs. 99.5%, respectively, during recovery period 1), whereas locoweed-novel feed averted sheep did not differ (P > 0.50) from averted sheep (0.6%). During the second recovery period, control sheep (100%) differed (P < 0.05) from averted (0%) and locoweed-novel feed averted (12.2%) groups. Two intoxicated sheep (locoweed-novel feed averted) partially extinguished the aversion during the first recovery period, but an additional dose of LiCl restored the aversion. Two of 3 intoxicated horses had strong aversions that persisted without extinction; 1 horse in the locoweed-novel feed averted group had a weaker aversion. These findings suggest that horses and sheep previously intoxicated by locoweeds can form strong and persistent aversions to a novel feed, but in some animals, those aversions may not be as strong as in animals that were never intoxicated.     

西藏疯草研究进展

通过查阅现有文献资料和实地调查结果表明,西藏共有疯草类有毒植物22种,其中棘豆属植物14种,黄芪属植物8种。疯草对西藏草地畜牧业生产危害十分严重,引起大批牲畜中毒死亡,造成严重经济损失;影响畜种改良,畜群结构严重失衡;破坏草地生态平衡,致使草地退化。西藏目前针对疯草的防除措施主要有人工挖除和应用化学除草剂灭除,并且应用解毒药物和生态控制工程预防和防治牲畜疯草中毒。疯草类植物虽然有毒,但含有较高的粗蛋白和含硫氨基酸,粗纤维含量较低,可作为动物饲料或药物进行开发利用。     

Conditioning taste aversions to locoweed (Oxytropis sericea) in horses

Locoweed (Oxytropis sericea) is a serious poisoning problem for horses grazing on infested rangelands in the western United States. Our objectives were to determine 1) whether lithium chloride or apomorphine would condition aversions to palatable foods, and at what doses, and 2) whether horses could be averted to fresh locoweed in a pen and grazing situation. Apomorphine was not an acceptable aversive agent because at the dose required to condition an aversion (> or = 0.17 mg/kg BW), apomorphine induced unacceptable behavioral effects. Lithium chloride given via stomach tube at 190 mg/kg BW conditioned strong and persistent aversions to palatable feeds with minor signs of distress. Pen and grazing tests were conducted in Colorado to determine if horses could be averted to fresh locoweed. Pen tests indicated that most horses (5/6) were completely averted from locoweed. Treated horses ate 34 g of fresh locoweed compared to 135 g for controls (P < 0.01) during three pen tests when offered 150 g per test. One horse (T) in the treatment group ate locoweed each time it was offered in the pen, but ate no locoweed while grazing. In the grazing trial, control horses averaged 8.6% of bites of locoweed (P < 0.01) during the grazing portion of the study, whereas treated horses averaged <0.5%. One treated horse (S) accounted for all consumption; he consumed 15% of his bites as locoweed in a grazing bout on d 2 of the field study. Thereafter, he was dosed a second time with lithium chloride and ate no locoweed in the subsequent 5 d. Three of six horses required two pairings of lithium chloride with fresh locoweed to condition a complete aversion. The results of this study indicate that horses can be averted from locoweed using lithium chloride as an aversive agent, and this may provide a management tool to reduce the risk of intoxication for horses grazing locoweed-infested rangeland.