丛枝菌根真菌在草地生态系统中的作用及应用潜力

丛枝菌根是一类重要的微生物资源,在生态环境建设和荒漠化治理中具有较高的应用价值。本文论述了丛枝菌根真菌资源、生理功能及在草地生态系统中的作用,草地生态建设中的应用潜力,指出菌根真菌在草地生态建设中具有广阔的应用前景,以期为研究草地生态建设、退化草地恢复、污染草地的修复以及荒漠化治理提供参考。     

新疆草地荒漠化过程及驱动因素分析

草地作为新疆生态环境的主体,其荒漠化的发生与发展关乎新疆的生态安全及生态环境质量。本研究通过对新疆草地生态系统分布规律、特征及利用现状的分析,从草地荒漠化过程及其与其他生态系统的相互关系入手,探讨自然因素和人为因素对草地荒漠化的影响。结果表明,1）新疆草地荒漠化过程分为两种类型,Ⅰ型为低山、平原荒漠类型草地的沙化、盐碱化和退化过程,Ⅱ型为山地草地类型的退化过程;2）在人类活动和水文环境变化的综合作用下,草地与耕地、沙地、林地、湿地和社区在荒漠化过程中可进行相互转化;3）地形地貌、气候和土壤等自然因素是草地荒漠化发展的背景条件,为草地荒漠化的发展提供了物质基础,气候变化是南疆和东疆盆地草地荒漠化的主要驱动因素之一;4）水资源不合理利用是各流域中下游草地荒漠化的主导因素,滥垦滥挖是绿洲周边草地荒漠化的直接导因,放牧场、割草场荒漠化的主要导因是长期超载、无序利用及草地建设投入严重不足。新疆草地荒漠化形成的驱动因素不仅具有多因素性、地域性的特点,而且具有交叉和叠加的综合特点和多营力综合作用特征。     

塔拉滩草地荒漠化成因分析及防治措施探讨

塔拉滩地处共和盆地,20世纪80年代以来,该地区草地退化、沙漠化加剧。通过研究1987和1996年TM卫星遥感影像解译以及1994和1999年沙漠化普查与监测结果,分析了塔拉滩草地荒漠化的原因主要有气候变化、生物因素、人为因素3个方面,针对这些原因提出了相应的防治措施：（1）封育禁牧;（2）人工促进退化草地恢复;（3）铺设沙障,沙障内种草植苗;（4）实施生态移民;（5）开发空中水资源;（6）以生态建设工程带动草地治沙事业。     

中国西部草原生态环境问题及其控制措施

草原是西部地区最脆弱的生态系统。草原生态环境建设是西部生态环境建设的主体和关键。本研究系统分析了西部地区草原的地位和作用,指出了草原生态环境状况、所面临的问题及其引发机理,查明了西部草原生态环境恶化的原因,确立了实施可持续发展模式,建立草地农业生态系统,是解决西部地区生态恶化、经济落后和社会不稳定的有效途径。总体建设上突出植被恢复和水土保持、遏制土地荒漠化;区域建设上突出水源涵养区、风沙区、水土流失区和自然保护区;产业发展上突出区域特色产业和绿色产业;项目选择上突出综合效益;技术选择上突出高新技术。并提出了西部草原生态保护、生态建设与可持续发展的对策措施。     

青海高寒牧区土壤荒漠化现状及防治对策的研究

草地是具有重要生态、经济功能和价值的自然资源。草地的天然牧草通过家畜转化，可为人类提供乳、肉、皮、毛等廉价畜产品，从而使草地畜牧业成为牧区经济和农牧民赖以生存和发展的支柱产业；草地作为陆地最大的生态系统，具有涵养水源、调节气候、防风固沙、美化环境、净化空气等生态功能，对维持生态平衡，维系生物多样性，保护人类生存环境发挥着巨大作用；与此同时，草地的自然景观和区域人文景观还具有重要的开发利用价值。因此，加强草地生态环境的保护和建设，不仅是经济发展的需要，而且对于提高人类的生存质量有着重要的意义。为此，本文对青海草地土壤荒漠化现状、原因、危害进行了初步的探索，提出了防治土壤荒漠化的基本思路及措施对策。     

甘南州鼠害与天敌调查报告

调查发现甘南境内有啮齿类动物50余种,其中危害草地的优势种是中华鼢鼠、达乌尔鼠兔、西藏鼠兔、根田鼠、喜玛拉雅旱獭等。提出在鼠害防治方面政府应从整个区域经济发展与生态系统可持续性的高度着眼,加大投资力度,集中人力、物力、财力进行连续、连片防治,做到防治一片,巩固一片;同时要从草地生态系统的整体性来考虑综合治理措施,努力恢复草地生态植被,提高草地生产能力。     

贵南县高寒草地荒漠化及其控制技术与措施

通过简述贵南县高寒干旱区草地类型、分布区域及荒漠化特征 ,从气候变化、鼠害、盲目开垦及超载过牧等自然、人为因素方面 ,分析总结了草地荒漠化引发机理 ,提出了防止草地荒漠化的对策及治理技术。     

景观生态学原理与方法在荒漠化研究中应用的理论分析

荒漠化发生发展的过程实际上是指在自然和人为因素的作用下，生态系统结构遭受破坏、功能过程受阻和演变发生异化的过程，其防治的根本措施是恢复和重建健康的生态系统。所以，景观生态学理念在荒漠化的研究和防治中有着重要的意义。本文从荒漠化与生态系统结构、功能变化、荒漠化与生物多样性、荒漠化生态系统的物质循环和能量流动以及荒漠化生态系统的稳定性等方面论述了景观生态学理念在荒漠化研究中应用的可行性，并重点分析了景观生态学关于景观格局变化的评价指标与荒漠化土地动态变化之间的关系。     

关于按生态经济区探寻畜牧业可持续发展对策的倡议

我国正由畜牧大国向畜牧强国迈进，可是还存在着影响畜牧业可持续发展和人民健康的制约因素。这些制约因素有：１　资源短缺的制约。我国大量草原、草山草坡、荒漠半荒漠未加有效地改良，沙化、碱化、荒漠化严重，从而造成草地资源短缺。农区蛋白质饲料长期短缺，加上玉米生产受生态地理条件和土壤质地的影响而发展潜力不足，分布区域不平衡，以及人均耕地面积少，因此农区饲料资源同样短缺。２　生态环境的制约。包括：（１）最突出的问题是草地生态系统遭到严重破坏，荒漠化面积已达国土面积的２７．３％。（２）农区生态环境也在不断恶化…     

红原县草地荒漠化现状及治理对策初探

分析了红原县草地荒漠化的现状及成因,针对现阶段红原县草原治理中存在的问题,提出应坚持以防为主、防治结合。特别是通过政策导向引导,各种经济形式融入到红原草原荒漠化的治理中,加大了草场建设资金的投入力度。     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

The Prevalence and Intensity of Helminth and Coccidial Infections in Dairy Cattle in Central Kenya

A survey of gastrointestinal parasite infections of young (<6 months old), immature (6–12 months old) and adult (>12 months old) dairy cattle on 16 farms in Kiambu District, Kenya was conducted during a dry season (September 1991 to January 1992) and during a wet season (March to July 1992). The survey was based on monthly coproparasitological examination of cohorts and worm counts in tracer calves. The effects of age, sex, farm and season on the prevalence and intensity of helminth and coccidial infections were determined. Faecal egg and oocyst counts revealed that the overall prevalences were: strongyles (including trichostrongyles) (85.5%), liver flukes (Fasciola gigantica) (34.0%), coccidia (30.9%) and tapeworms (9.6%). Eight species of the protozoan Eimeria were identified, the most prevalent species being E. bovis and E. zuernii. The most prevalent nematode genera were Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus. Season, farm and age of the animals had a significant (p<0.05) influence on the intensity of infection with strongyles, liver flukes and coccidia, whereas the sex of the animals had no significant (p>0.05) effect on the prevalence or intensity of infections. A higher intensity of infection with strongyles and coccidia was found in the wet season than in the dry season (p<0.05). The age-specific intensity was in the following order: for strongyles, immature animals of 6–12 months of age had the highest egg counts, followed by young calves and adults. Calves had significantly (p<0.05) higher oocyst counts than immatures or adults. Liver fluke egg counts did not differ significant (p>0.05) between immatures and adult cattle.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Hypothalamic dopamine is required for salsolinol‐induced prolactin secretion in goats

The aim of the present study was to clarify the relationship between hypothalamic dopamine (DA) and salsolinol (SAL) for the secretion of prolactin (PRL) in goats. SAL or thyrotropin‐releasing hormone (TRH) was intravenously injected into female goats treated with or without the D₂ DA receptor antagonist haloperidol (Hal), which crosses the blood‐brain barrier, and the PRL‐releasing response to SAL was compared with that to TRH. PRL‐releasing responses to SAL, Hal, and Hal plus SAL were also examined after a pretreatment to augment central DA using carbidopa (Carbi) and L‐dopa. The PRL‐releasing response to Hal alone was greater than that to SAL or TRH alone. The PRL‐releasing response to Hal plus SAL was similar to that of Hal alone. In contrast, the PRL‐releasing response to Hal plus TRH was greater than that to TRH or Hal alone. The treatment with Carbi plus L‐dopa inhibited SAL‐ and Hal‐induced PRL secretion. The inhibition of the PRL‐releasing response to SAL disappeared when SAL was injected with Hal. These results indicate that the mechanisms underlying the SAL‐induced PRL response differ from those of TRH, and suggest that hypothalamic DA and its synthesis is associated in part with SAL‐induced PRL secretion in goats.     

Laboratory diagnosis of respiratory diseases of cattle

The authors describe the procedure of laboratory diagnosis for bovine respiratory diseases: direct diagnosis by isolation and for identification of bacteria or viruses and indirect diagnosis by serological methods. They specify the restraints and limits of this diagnosis and the significance results which are obtained and connected with knowledge of anamnestic information.     

The effect of peri-parturient anthelmintic treatment on the productivity of dairy cattle in subtropical western India

Trials with fenbendazole (Panacur, Hoechst India Ltd) were carried out on two commercial farms in subtropical western India to study the response and economics of nematode treatment in adult dairy cows. Milk yield, lactation length, time to first oestrus and worm egg output were monitored in treated and control groups. Treatment reduced the egg count considerably. Treated cows produced 142 litres more milk over 100 days (p<0.05), with extension of lactation length and advancement of time to first oestrus. The economic gain in terms of milk yield far outweighed the cost of anthelmintic used.     

An Evaluation of the Acceptability as Forage of Some Nutritive and Antinutritive Components and of the Dry Matter Degradation Profiles of Five Species of Ficus

The suitability of five species of Ficus, F. mucoso, F. thonningii, F. polita, F. religiosa and F. benjamina, for feeding ruminant livestock was studied. The nutritive and antinutritive components were determined and the acceptability of the forages to livestock was assessed using a cafeteria method in 8 adult small ruminants. Also, the degradation potential of the dry matter of the five Ficus species was investigated using 3 fistulated sheep. The crude protein (CP) content of the Ficus species varied significantly (p < 0.05), ranging from 130 to 180 g/kg DM. The content of neutral detergent fibre (NDF) also varied significantly (p < 0.05), ranging from 650 to 710 g/kg DM. The organic matter (OM) contents did not differ significantly (p > 0.05), having a mean value of 916 g/kg DM. The concentrations of tannin, saponin, phytic acid and oxalic acid were low. The acceptability of the forage was similar for four of the species but poor for F. polita. The extent of DM degradation varied significant among the Ficus species, the ranking order being F. benjamina > F. thonningii > F. mucoso > F. religiosa > F. polita.