藏北草原牧民可持续生计分析—以班戈县为例

运用实地调查的方法,对藏北草原牧业户和兼业户进行比较分析和回归分析,以期提高人们对藏北草原牧民生计状况的认识,并对藏北草原牧民生活水平提升和收入增长提供一定的参考依据。结果表明:班戈县牧业户呈现"低质化"特征;兼业户的资本禀赋要好于牧业户;拥有较多自然资本和经济资本的牧户习惯于以单纯依靠牧业收入作为其生计策略;拥有较多人力资本、物质资本和社会资本的牧户更愿意选择多种经营方式来获取更多收入;物质资本对牧户生计策略的影响最为显著,社会资本显著程度不高,而人力资本存量偏低。总体来说,牧民生计在提升藏北草原牧民生活水平和促进牧民收入提高过程中显得更加急迫和重要。     

Variant surface glycoproteins from Venezuelan trypanosome isolates are recognized by sera from animals infected with either Trypanosoma evansi or Trypanosoma vivax

Salivarian trypanosomes sequentially express only one variant surface glycoprotein (VSG) on their cell surface from a large repertoire of VSG genes. Seven cryopreserved animal trypanosome isolates known as TeAp-ElFrio01, TEVA1 (or TeAp-N/D1), TeGu-N/D1, TeAp-Mantecal01, TeGu-TerecayTrino, TeGu-Terecay03 and TeGu-Terecay323, which had been isolated from different hosts identified in several geographical areas of Venezuela were expanded using adult albino rats. Soluble forms of predominant VSGs expressed during the early infection stages were purified and corresponded to concanavalin A-binding proteins with molecular masses of 48–67 kDa by sodium dodecyl sulfate-polyacrylamide gel electropohoresis, and pI values between 6.1 and 7.5. The biochemical characterization of all purified soluble VSGs revealed that they were dimers in their native form and represented different gene products. Sequencing of some of these proteins yielded peptides homologous to VSGs from Trypanosoma (Trypanozoon) brucei and Trypanosoma (Trypanozoon) evansi and established that they most likely are mosaics generated by homologous recombination. Western blot analysis showed that all purified VSGs were cross-reacting antigens that were recognized by sera from animals infected with either T. evansi or Trypanosoma (Dutonella) vivax. The VSG glycosyl-phosphatidylinositol cross-reacting determinant epitope was only partially responsible for the cross-reactivity of the purified proteins, and antibodies appeared to recognize cross-reacting conformational epitopes from the various soluble VSGs. ELISA experiments were performed using infected bovine sera collected from cattle in a Venezuelan trypanosome-endemic area. In particular, soluble VSGs from two trypanosome isolates, TeGu-N/D1 and TeGu-TeracayTrino, were recognized by 93.38% and 73.55% of naturally T. vivax-infected bovine sera, respectively. However, approximately 70% of the sera samples did not recognize all seven purified proteins. Hence, the use of a combination of various VSGs for the diagnosis of animal trypanosomosis is recommended.     

An overview of animal science research 1945–2011 through science mapping analysis

The conceptual structure of the field of Animal Science (AS) research is examined by means of a longitudinal science mapping analysis. The whole of the AS research field is analysed, revealing its conceptual evolution. To this end, an automatic approach to detecting and visualizing hidden themes or topics and their evolution across a consecutive span of years was applied to AS publications of the JCR category ‘Agriculture, Dairy & Animal Science’ during the period 1945–2011. This automatic approach was based on a coword analysis and combines performance analysis and science mapping. To observe the conceptual evolution of AS, six consecutive periods were defined: 1945–1969, 1970–1979, 1980–1989, 1990–1999, 2000–2005 and 2006–2011. Research in AS was identified as having focused on ten main thematic areas: ANIMAL‐FEEDING, SMALL‐RUMINANTS, ANIMAL‐REPRODUCTION, DAIRY‐PRODUCTION, MEAT‐QUALITY, SWINE‐PRODUCTION, GENETICS‐AND‐ANIMAL‐BREEDING, POULTRY, ANIMAL‐WELFARE and GROWTH‐FACTORS‐AND‐FATTY‐ACIDS. The results show how genomic studies gain in weight and integrate with other thematic areas. The whole of AS research has become oriented towards an overall framework in which animal welfare, sustainable management and human health play a major role. All this would affect the future structure and management of livestock farming.     

Genetic management of Dutch golden retriever dogs with a simulation tool

Excessive inbreeding rates and small effective population sizes are an important problem in many populations of dogs. Proper genetic management of these populations can decrease the problem, and several measures are available. However, the effectiveness of these measures is not clear beforehand. Therefore, a simulation model was developed to test measures that aim to decrease the rate of inbreeding. The simulation program was used to evaluate inbreeding restriction measures in the Dutch golden retriever dog population. This population consisted of approximately 600 dams and 150 sires that produce 300 litters each year. The five most popular sires sire approximately 25% of the litters in a year. Simulations show that the small number of popular sires and their high contribution to the next generation are the main determinants of the inbreeding rates. Restricting breeding to animals with a low average relatedness to all other animals in the population was the most effective measure and decreased the rate of inbreeding per generation from 0.41 to 0.12%. Minimizing co‐ancestry of parents was not effective in the long run, but decreased variation in inbreeding rates. Restricting the number of litters per sire generally decreased the generation interval because sires were replaced more quickly, once they met their restriction. In some instances, this lead to an increase in inbreeding rates because the next generations were more related. The simulation tool proved to be a powerful and educational tool for deciding which breeding restrictions to apply, and can be effective in different breeds and species as well.     

如何在超大城市的中心绿地营造特色生态微栖息地景观?——以深圳中心公园为例

为探索如何在现有公园基础上构建特色生态微栖息地,以深圳中心公园特色动植物调查为基础,明确中心公园趣味生态资源,进一步梳理周边生态系统和整体植被基底、筛选特色动物服务对象、融合公园整体规划与景观,力求构建12个具有本地特色的,超大城市中心绿地的动植物生态微栖息地,形成更多动物的觅食地、夜栖地乃至繁殖地,力求整体提升该区域的生物多样性,也利于形成城区内的生态“跳岛”和自然教育“网红”节点。     

Infection dynamics of foot-and-mouth disease virus in pigs using two novel simulated-natural inoculation methods

In order to characterize foot-and-mouth disease virus (FMDV) infection dynamics in pigs, two simulated-natural inoculation systems were developed and evaluated. Intra-oropharyngeal (IOP) and intra-nasopharyngeal (INP) inoculation both enabled precise control of dose and timing of inoculation while simulating field exposure conditions.     

Genetic parameters for direct and maternal calving ease in Walloon dairy cattle based on linear and threshold models

Calving ease scores from Holstein dairy cattle in the Walloon Region of Belgium were analysed using univariate linear and threshold animal models. Variance components and derived genetic parameters were estimated from a data set including 33 155 calving records. Included in the models were season, herd and sex of calf × age of dam classes × group of calvings interaction as fixed effects, herd × year of calving, maternal permanent environment and animal direct and maternal additive genetic as random effects. Models were fitted with the genetic correlation between direct and maternal additive genetic effects either estimated or constrained to zero. Direct heritability for calving ease was approximately 8% with linear models and approximately 12% with threshold models. Maternal heritabilities were approximately 2 and 4%, respectively. Genetic correlation between direct and maternal additive effects was found to be not significantly different from zero. Models were compared in terms of goodness of fit and predictive ability. Criteria of comparison such as mean squared error, correlation between observed and predicted calving ease scores as well as between estimated breeding values were estimated from 85 118 calving records. The results provided few differences between linear and threshold models even though correlations between estimated breeding values from subsets of data for sires with progeny from linear model were 17 and 23% greater for direct and maternal genetic effects, respectively, than from threshold model. For the purpose of genetic evaluation for calving ease in Walloon Holstein dairy cattle, the linear animal model without covariance between direct and maternal additive effects was found to be the best choice.     

Optimizing the use of breed types in developing country livestock production systems: a neglected research area

Developing country livestock production systems are diverse and dynamic, and include those where existing indigenous breeds are currently optimal and likely to remain so, those where non‐indigenous breed types are already in common use, and systems that are changing, such as by intensification, where the introduction of new breed types represents significant opportunities. These include opportunities to improve the livelihood of the world's poor, increase food and nutrition security and enhance environmental sustainability. At present, very little research has focused on this issue, such that significant knowledge gaps in relation to breed‐change interventions remain. The purpose of this study is to raise awareness of this issue and suggests strategic research areas to begin filling these knowledge gaps. Such strategic research would include (i) assessing the impact of differing breed types in developing country livestock productions systems, from a range of viewpoints including intrahousehold livelihood benefit, food and nutrition security at different scales, and environmental sustainability; (ii) identification of specific livestock production systems within developing countries, and the type of livestock keepers within these system, that are most likely to benefit from new breed types; and (iii) identification of new breed types as candidates for in‐situ testing within these systems, such as through the use of spatial analysis to identify similar production environments combined with community acceptance studies. Results of these studies would primarily assist stakeholders in agriculture, including both policy makers and livestock keepers, to make informed decisions on the potential use of new breed types.     

动物行为与动物园安全管理

野生动物的行为是动物与环境相互作用的结果,动物园中动物的行为也反映出动物与相应的由人为提供的环境之间的关系。本文分析了现阶段在动物园圈养人工控制的环境下,动物展现出的有关动物行为如领域行为、攻击行为、交配行为、学习行为、摄食行为、警戒行为和体温调节行为等,以及由这些行为导致的安全问题,并有针对性地提出了在动物管理中相应的防范措施与解决办法。在动物园日常管理工作中,工作人员要熟知动物行为的目的与意义,观察动物行为,及时发现动物的不适与异常,充分掌握与安全有关的动物行为并及时分析,找出可能存在的对动物造成伤害的安全隐患,避免安全事故,给动物提供更舒适安全符合动物生物学特性的环境,同时也是提高动物福利的重要环节。     

北美落基山自然风光与动植物纪事

北美洲落基山脉纵贯加拿大西南和美国西北部,跨越北极带、寒带和温带高原气候带,是全球著名山脉之一。有奇特的高原地貌、世界最大的冰原、众多冰河、瀑布、高原湖泊、温泉及间歇喷泉等自然景观,以及多种植被、特有动物,每年吸引来自世界各地的众多游客。美国、加拿大政府和联合国教科文组织重视环保,在落基山脉建立众多国家公园,其中有7处划定为《世界遗产目录》《世界遗产公园》。国家公园重视环保,订立各种保育措施,值得借鉴。