青藏高原牧户草地转入行为的影响因素分析——基于495户牧民的调查

以玉树、那曲、阿坝、甘南4个地区共495个牧户调研数据为基础,运用Logit和Probit实证计量模型从户主个人特征、家庭社会经济特征、牧民草场畜牧业经营特征和其他因素等方面分析了青藏高原牧区草地转入行为的影响因素。结果表明:牧户家庭草地承包面积对草地转入行为有显著的负向影响,牲畜数量对草地转入行为有显著的正向影响;区域变量中,那曲地区牧户的草地转入行为显著低于其他3个地区,而甘南和阿坝牧户的草地转入行为显著高于另外两个地区。根据上述结果,对促进牧区草地的有序流转提出了建议。     

东乌珠穆沁旗牧户草地流转中的转入行为

为提升牧民的草地流转意愿，促进牧区草地的规模化经营。基于二元Logistic模型和逐步回归的步骤和要求，从牧户个人特征、家庭特征、资源特征、草地特征4个方面，对东乌珠穆沁旗牧户牧草地转入行为及规模的影响因素进行实证分析。结果表明：牧区草地流转已初具规模，以集体经济组织内部流转为主，草地主要集中在分散牧户手中；集中各项资源优势的牧户倾向于转入草地；草地转入规模受多种变量的影响。因此，建议逐步推动牧区草原承包经营权流转市场；完善流转户的相关保障制度；加强草原承包经营权的宣传力度，提高牧户意识；加大教育投入，培育新型规模经营主体。     

草原补奖政策对牧户牧业生产决策行为的影响研究

我国实施草原生态保护补助奖励政策已历经7年,实证分析该政策对牧户牧业决策行为的影响,对于完善第二期补奖政策和牧户生产决策行为的深入研究具有积极意义。研究基于草原补奖政策实施前后甘肃省牧区及半农半牧区7个县220户牧户的调查,运用Logistic模型和负二项回归模型分析了草原生态补奖政策对牧户生产决策行为的影响。结果表明:草原补奖政策对牧户的生产决策行为总体上产生了显著正向影响,但对半农半牧区牧户牧业生产决策行为的影响高于牧区;草原补奖政策并不是影响牧户生产决策行为的唯一因素,除补奖政策外,牧户生产决策行为影响因素具有非对称性。从前期牧户扩大牧业生产规模的可能性来看,牧区主要受家庭特征因素的影响,而半农半牧区主要受外部环境因素的影响。从后期牧户扩大多少牧业生产规模来看,牧区牧户关注更多的是资金、牧业生产的风险保障和饲草储备,而半农半牧区牧户则侧重于收入来源、市场行情和饲草储备。最后建议重视荒漠化草原类型,综合牧户家庭特征,实施差异化补贴;切合牧户需求,提高牧户主体决策水平,实现牧业生产效益最大化。     

草原补奖政策对牧户牧业生产决策行为的影响研究

我国实施草原生态保护补助奖励政策已历经7年,实证分析该政策对牧户牧业决策行为的影响,对于完善第二期补奖政策和牧户生产决策行为的深入研究具有积极意义。研究基于草原补奖政策实施前后甘肃省牧区及半农半牧区7个县220户牧户的调查,运用Logistic模型和负二项回归模型分析了草原生态补奖政策对牧户生产决策行为的影响。结果表明:草原补奖政策对牧户的生产决策行为总体上产生了显著正向影响,但对半农半牧区牧户牧业生产决策行为的影响高于牧区;草原补奖政策并不是影响牧户生产决策行为的唯一因素,除补奖政策外,牧户生产决策行为影响因素具有非对称性。从前期牧户扩大牧业生产规模的可能性来看,牧区主要受家庭特征因素的影响,而半农半牧区主要受外部环境因素的影响。从后期牧户扩大多少牧业生产规模来看,牧区牧户关注更多的是资金、牧业生产的风险保障和饲草储备,而半农半牧区牧户则侧重于收入来源、市场行情和饲草储备。最后建议重视荒漠化草原类型,综合牧户家庭特征,实施差异化补贴;切合牧户需求,提高牧户主体决策水平,实现牧业生产效益最大化。     

基于牧户行为的草地管理模式——以西藏自治区为例

本研究利用产量和利润最大化理论,基于随机抽样调查构建多元选择模型,探讨不同类型牧户放牧决策差异及导致牧户过度放牧的内在机制,分析牧民家庭收入、畜牧业科技推广、草地管理投入、牧户兼业行为和风险意识等变量对牧户放牧决策的影响,模拟不同政策组合下过度放牧牧户降低牲畜存栏量的意愿。研究表明,1)牧户生产决策受畜产品价格影响大,然而,不同质量畜产品价格差异小,导致牧民忽略畜产品品质而过度追求存栏量,引致草地禁牧政策失效;2)牦牛饲养比重对牧户减少牲畜存量的边际倾向值最大,比重每增加1单位,牧户意愿降低牲畜存栏量5.684单位,由于牦牛饲养草地需求较多,对是否降低存栏量敏感;3)大部分牧户倾向于选择经济效益,寻找兼顾生态与经济,能够有效提高牧户参与的区域生态经济发展战略是未来西藏牧区生态保护与经济发展策略的核心。     

浑善达克沙地草地放牧制度和特殊经营管理行为的研究

草地放牧制度不仅反映畜牧业生产的特征.也决定其性质.草地放牧制度选择的合理与否,直接影响草地资源的可持续利用和草地生态环境质量以及牧户经营收入.在阐述草原牧区草地放牧制度演变的基础上,采用基于随机抽样的人户调查和实地考察的方法,对位于浑善达克沙地的6个苏木290个牧户进行了调查研究,分析了牧户草地放牧制度的不同类型以及草地利用中的经营管理行为.     

冻原高山草地牧户家畜养殖规模影响因素分析——以青海省为例

家畜养殖规模是草地载畜的重要组成部分,对其影响因素进行深度剖析,对于引导牧户合理放牧,遏制草地退化,确保我国生态安全意义重大。根据在青海省调查获取的牧户数据,本研究运用主成分分析法识别了冻原高山草地上相关因素对牧户家畜养殖量的贡献率,进一步采用分位数回归深入剖析了不同规模牧户家畜养殖量的影响因素及其影响规律,探索家畜养殖影响因素在牧户规模层面的异质性。结果表明：冻原高山草地牧户家畜养殖量的主导现实因素为自然因子,其余影响因素依次是政策因子、教育因子和非牧因子;中等以下规模牧户家畜养殖量受家庭劳动力和非牧就业收入占比的显著影响;中等及以上规模牧户家畜养殖量受人均经营草地面积和草原补奖政策的显著影响,补奖政策中禁牧比草畜平衡更能达到保护草地生态的目标。建议增加牧区非牧就业机会,积极引导中等以下规模牧户参与非牧就业,同时加大冻原高山草地禁牧范围,并在补偿标准上对中等及以上规模牧户适当倾斜。本研究发现了冻原高山草地上家畜养殖影响因素在牧户规模上的异质性,为政府针对不同规模牧户区分管理提供了一定的科学依据。     

草原生态补奖政策下牧户认知对其支持和行为响应的影响分析

牧户对政策的支持和行为响应是影响草原生态补奖政策实施效果和可持续性的关键所在。利用内蒙古自治区扎鲁特旗和四子王旗217份调研数据,通过构建结构方程模型实证研究牧户政策认知对其支持和行为响应的影响,并进一步分析约束性条件作为调节变量对牧户支持和行为响应产生的直接影响路径效应与间接影响路径效应。结果表明：牧户的政策认知对其支持和行为响应的标准路径系数为0.987,具有显著的正向促进作用;约束性条件中,个人及家庭特征、交通因素、经济因素与牧户支持和行为响应的关系存在以认知程度为中介的间接影响路径效应,交通因素与监督力度存在直接影响路径效应。因此,政府应切实加强政策的宣传工作,同时配套相关措施包括注重对牧户非农牧劳动力就业的引导、提高文化教育水平、提供便利的交通条件等,调动牧户对政策支持与自主参与减畜的积极性,从而促进牧区振兴。     

天山自然遗产地亚高山草甸放牧管理方式比较

以天山自然遗产地喀拉峻亚高山草甸为研究对象,2014年7月底到8月初,研究了现有不同管理方式——禁牧、限牧和放牧对草地植物群落和土壤的影响.结果表明,与放牧区相比,禁牧区物种总数、植被盖度和地上生物量显著提高(P＜0.05),而α物种多样性水平则没有显著变化(P＞0.05);而限牧区草地不仅植物群落种类最为丰富、α物种多样性最高,植被盖度和地上生物量也与禁牧区接近.禁牧导致草地土壤养分含量下降,不同放牧方式下草地土壤养分含量总体呈放牧＞限牧＞禁牧变化趋势.因此,在喀拉峻自然遗产地现有的3种管理方式中,禁牧并非是最好的草地恢复方式,限牧是相对可行的管理方式.     

草场从承包到“再集中”经营牧民响应吗?——基于内蒙古试点嘎查全样本微观数据分析

内蒙古呼伦贝尔市M嘎查率先创新牧区集体经济运行机制,成立股份制专业合作社,对草场经营权"再集中",实现草场的统一管理。本研究以M嘎查的全样本牧户为研究对象,构建计量模型,从家庭禀赋因素、经济因素和政策因素三个方面探索了牧民参与行为的影响机制。结果表明:牧民家庭非畜牧业收入占比、是否有贷款正向影响其参与行为。不同草场规模牧户的参与行为影响因素存在差异,就大牧户而言,畜牧业家庭劳动力人数负向影响其参与行为,家庭总收入和兼业收入占比则正向影响其参与行为;而对中小牧户来说,草场是否发生流转与其参与行为呈显著负相关。结合以上结论,笔者从建立生态、经济、社会保护利用机制,提高金融部门支持力度,根据不同牧户分类引导等角度提出了促进牧区股份制专业合作社发展的对策建议。     

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.     

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

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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