玉树县草地退化现状及治理措施

通过调查资料分析,玉树县现有退化草地597533.3hm2,占可利用草场面积的43.56%。草地退化的主要原因是:超载过牧,鼠虫危害以及滥采乱挖等人为因素。并提出了加强草地建设,实施退耕还林(草),退牧还草和三江源生态保护治理等项目工程以及逐步完善和实行以法治草,建立人工草地等措施。     

西藏班戈县草地退化动态变化及其驱动力分析

为了监测班戈县近20年(1990-2009年)草地退化状况,利用3个时相的TM和ETM数据,以及CEBERS数据,分别提取了班戈县的植被指数,并通过植被指数转化模型计算出植被覆盖度。按植被覆盖度将草地划分为4个不同退化等级,比较了班戈县近20年草地退化情况,分析了草地退化的原因。结果表明:草地退化面积前10年(1990-1999年)呈增加趋势,后10年(2000-2009年)呈减少趋势,从总体变化趋势看,草地退化面积在不断增加。造成草地退化的原因包括自然原因如气候高寒、干旱,土壤贫瘠、鼠虫害,以及人为因素如超载、不合理的开采活动以及滥挖药材等。     

模糊层次分析法在西藏草地退化研究中的应用

针对西藏草地退化的成因以及恢复治理措施的效应问题,利用模糊层次分析法,研究了西藏草地退化的成因和各种恢复治理措施的效率。结果表明,超载放牧对西藏草地退化的贡献率达到45.6%,气候变化异常、自然条件恶劣的贡献率是30.43%,两者是导致西藏草地退化的主要原因;其次是鼠虫毒杂草危害,贡献率占11.4%;治理措施层各因素对总目标权重的大小顺序为:围栏封育和划区轮牧(0.2078)建立人工草地(0.1459)降低放牧强度(0.1402)鼠虫和毒杂草控制(0.1337)停止滥挖乱采活动(0.1211)施肥、补播、松耙(0.1059)优化畜群结构(0.0939)优良牧草选育(0.0515)。实行围栏封育和划区轮牧是治理草地退化的有效措施,而建立人工草地、控制鼠虫和毒杂草、停止滥挖乱采活动、施肥、补播、松耙等措施也不能忽视,草地退化治理应该是一个综合治理的过程。     

兴海县草地保护建议

经调查,兴海县退化草地面积占可利用草地面积的22．31％。其中,严重退化草地面积为1．14×104hm2,中度退化草地8．8×104hm2,轻度退化草地10．97×104hm2;草地退化使草地产草量从1982年的2760kg／hm2下降到2002年的1575kg／hm2,下降了42％;掠夺式放牧、鼠虫害严重、毒杂草蔓延、“四滥”不禁及人口快速增长是导致草地退化的主要原因;建议采取依法治草,加强草地建设,科学合理利用草地,加强教育等措施保护草地。     

浑善达克沙地草地植被恢复效益遥感监测

一、前言 浑善达克沙地是中国五大沙地之一,地处锡林郭勒高原中部.长期以来由于对草地资源的过度开垦、超载过牧、滥采滥挖,草地退化、沙化日趋严重,草地生态环境明显恶化,为遏制沙地生态系统的进一步退化,2000年国家启动了京津风沙源治理工程,以期通过人工林与人工草地建植、围栏封育、飞播改良等措施恢复草地植被,遏制草地退化、沙化的扩展趋势. 笔者旨在应用多学科、多种技术集成的手段,以3S技术(遥感RS,地理信息系统GIS,全球定位系统GPS)为主,比较工程实施前后草地植被群落变化,评价浑善达克沙地工程实施后草地植被恢复效益,为促进草地畜牧业可持续发展和保护生态环境提出切实可行的科学依据.     

江河源区草场退化的生态环境后果及成因

江河源区是我国五大牧区之一,然而由于自然环境变迁与人类活动的影响,草地生态环境日趋恶化.突出表现为:草地生产力下降、沙化、草地植被减少、草地生态系统恶化.草地生态系统退化是人为因素与自然因素综合作用的结果,尤其是人类活动(如过渡放牧、不合理的放牧制度、滥挖、滥垦等)的加剧成为草地退化和草地生态环境恶化的"加速器".     

甘肃黄河上游主要生态功能区草原退化成因及治理对策浅析

造成甘肃黄河上游主要生态功能区天然草地退化的主要原因有:气候旱化,滥挖、滥垦、滥采和不合理草地利用,草地超载过牧及鼠虫害严重。调控及治理对策:建立合理的经营管理制度,确定合理载畜量,实行禁牧休牧制度;开展草原改良,加快退化草地治理,加大科技推广力度,改变落后的生产方式。调查其退化的程度、面积和成因,对保护高寒牧区草原生态环境、合理利用草原具有重要意义。研究表明,实行科学管理,严格禁牧、休牧制度,开展草原改良,实行生态补偿机制,可以有效缓解草原退化。     

草地生态的恢复与保护

多年来,我国北方草地由于超载的人口、滥垦、滥牧、滥采、滥伐造成大面积的草地退化、沙化,生态环境恶化。文章阐释了草地沙漠化的成因、现状,提出了国家必须高度重视、全民行动、长期坚持才能解决草地生态问题,遵循客观规律保护、建设和利用草地及恢复自然生态的思考和建议。     

青藏高原边缘地区草地利用现状及持续利用策略——以天祝县为例

位于青藏高原边缘地区的天祝县天然草地普遍退化,严重退化草地面积占草地总面积的34.4％。草地覆盖度、高度和产量较20世纪50年代分别下降了11.11%、41.7%和30.4%;草地群落内物种数下降,禾本科比例降低,毒杂草比例增加。草地退化主要因素包括气候干旱化、季节性超载、鼠虫危害、乱采滥挖。针对草地资源利用现状和草地生态建设的薄弱环节,提出草地资源持续利用策略。     

青海无鼠害示范区建设成效显著

草原鼠害因其分布广泛 ,对草地生态环境、草地生产力以及草地畜牧业造成的破坏很大 ,是加剧草地退化、沙化的主要因素之一。切实抓好草原鼠害防制工作 ,对于保障牧区经济的发展和改善草地生态环境具有十分重要的现实意义。青海省位于青藏高原东北部 ,是我国重要的牧区之一。全省六州一地一市 ,90 %以上的地域是草原牧区 ,共有草地面积5 47亿亩 ,其中可利用草地面积4 74亿亩 ,占全省土地总面积的50 64 %。近年来 ,随着全球性气候变暖、变干以及鼠虫害泛滥等自然因素和超载过牧、滥采滥伐、重利用、轻保护等人为因素的影响 ,草地退化面积逐年…     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

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.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -