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1.
C. M. Arriaga-Jordán A. M. Pedraza-Fuentes E. G. Nava-Bernal M. C. Chávez-Mejía O. A. Castelán-Ortega 《Human ecology: an interdisciplinary journal》2005,33(6):821-845
Livestock agrodiversity of Mazahua smallholder ‘campesino’ systems in the highlands of Central Mexico was investigated in the villages of San PabloTlalchichilpa (SPT) and La Concepción Mayorazgo (LCM). An animal inventory of 142 households in the two villages was made, followed by the monthly monitoring of 25 households
through interviews and participant observation. Thirteen species of domestic animals were found, with a median of three species
per farm. The main species werechickens, donkeys, sheep, cattle, mules, and horses, with some also keeping rabbits, ducks,
and pigeons. Draught animals are fundamental. Poultry represents a dynamic asset that provides food, income, and short-term
savings. Sheep are medium-term savings, and providestability. Livestock are managed in interaction with crops, providing draught
force, manure, and cash, and receiving feed. Livestock are fed weeds of the maize crop and stover dring the dry season. Donkeys
and sheep are also grazed on common land and in the fields after harvest. High prices for sheep have meant more flocks with
possible detrimental environmental effects. Men usually own the draught animals, although anyone may own animals. Women are
commonly owners of small stock and receive animals as wedding presents or inheritance. Other arrangements include shared ownership
and borrowing. Livestock and produce may be traded in regional markets but are generally sold locally.,Campesinos are aware of unfavorable local terms, but reckon possible benefits do not warrant increased transportation costs and time.
The villagers say their animals allow them to meet their needs and remain in their villages while improving their livelihoods. 相似文献
2.
Small ruminant production in smallholder and pastoral/extensive farming systems in Kenya 总被引:1,自引:0,他引:1
A survey was conducted by way of personal interviews with 562 respondents comprising 459 farmers and 103 butchers/traders in selected districts in the central and western parts of Kenya, consisting of three predominantly smallholder and four predominantly pastoral/extensive districts. The study aimed to provide a better understanding of smallholder and pastoral/extensive sheep and goat farming systems in the tropics, by taking Kenya as an example. The results showed that 58% of the pastoral/extensive farmers and 46% of the smallholders indicated livestock as their main activity. Small ruminants ranked closely behind cattle in their importance. Thirty-four percent of the households kept only sheep, 18% only goats and 48% both species. The survey demonstrated the relative importance to the farmers of tangible benefits of farming sheep and goats (e.g., regular cash income, meat, manure and, in the case of goats, milk) versus intangible benefits (e.g., the role of small ruminants as an insurance against emergencies). Regular cash income and an insurance against emergencies were the highest priorities. Seventy-eight percent of the farmers reported animal sales over the previous 12 months of the survey date. Of these sales, the income was spent on school fees (32%), purchase of food (22%), farm investment (18%), medical expenses (10%), off-farm investment (9%), social activities (5%) and re-stocking (4%). Indigenous genotypes were predominant among the pastoralists and mixed crosses predominant among the smallholders. A range of traits: growth rate, body size, body shape, drought tolerance, meat quality, fertility, disease and heat tolerance, prolificacy and temperament were all considered important for both sheep and goats in both farming systems and across the different genotypes. Compared with other pure breeds, the Red Maasai sheep and the Small East African goats were rated poorly in terms of body size, body shape, growth and fertility, but highly in terms of drought and (for the Red Maasai) heat tolerance by both smallholder and pastoralist farmers. In general, crosses were perceived less favourably than indigenous pure breeds. Body size and performance ranked as the most important traits in the choice of breeding males. Approximately half the farmers inherited their males, reared them on the farm and kept them for an average of 2–3 years. Uncontrolled mating within the household's flock was predominant in both farming systems. Over 98% of the farmers reported incidence of disease, especially pneumonia (in pastoral/extensive areas), helminthosis, tick-borne diseases, diarrhoea and foot-rot. Over 95% of the farmers fed supplements in both dry and wet seasons. Pure exotic and indigenous × exotic genotypes fetched higher prices than indigenous genotypes due to their heavier body weight. In conclusion, the foregoing issues need attention in genetic improvement programmes, with more emphasis on the conservation and utilisation of indigenous small ruminant genotypes. 相似文献
3.
Laboratory‐based seed storage systems have been developed as an alternative to in situ conservation for indigenous woody plant species. However, interactions between seed quality and environmental variables must be known for each species prior to seed collection, storage and sowing to ensure effective conservation. This study investigated Acacia tortilis seed weight/quality patterns across seven Botswana seed provenances in relation to: soil nutrient status, altitude; latitude; slope angle; % grass cover; height and density of other woody plants nearby. The higher rainfall and relatively eutrophic seed provenances of north‐western Botswana (Chobe, Okavango and Makgadikgadi) were associated with large A. tortilis species and seeds, as well as higher densities of woody plants. Spatial variation in seed weights of A. tortilis was principally a function of rainfall and soil organic carbon. Although more work is required to establish the relationship between seed weight and germination rates for A. tortilis, this research suggests that seed collection should focus on sites with high levels of rainfall and soil organic carbon. 相似文献
4.
Gidey Yirga Hans H. De Iongh Herwig Leirs Kindeya Gebrehiwot Gebrehiwot Berhe Tsehaye Asmelash Haftu Gebrehiwot Hans Bauer 《African Journal of Ecology》2013,51(1):78-86
The degradation and fragmentation of the northern Ethiopian highlands has resulted in frequent encounters of large carnivores with humans and their livestock. We interviewed 500 randomly selected households to estimate economic impact of livestock predation by spotted hyaena (Crocuta crocuta), leopard (Panthera pardus) and jackal (Canis aureus aureus) in the highlands of northern Ethiopia. The annual mean economic loss per household was approximately U.S.$ 20.2, about 7% of the average annual income of households in the area. Households surveyed reported losses of a total of 3122 livestock to hyaena, leopard and jackal predation over the past 5 years. This loss equated to a total financial loss of U.S.$ 50,381 . Livestock predation incidents of spotted hyaena, leopard and jackal demonstrated that spotted hyaena had a preference for dog, donkey, goat and sheep; leopard for goat, dog and sheep; and jackal for goat and sheep. Livestock predation of spotted hyaena and leopard were mainly during the night. We conclude that assessing depredation problems is important to develop actions for management of either livestock practices or wildlife conservation. 相似文献
5.
Michel Mainack Dione Amadou Sry Cheick Abou Kounta Sidib Barbara Wieland Abdou Fall 《PLoS neglected tropical diseases》2022,16(4)
An important problem for livestock production in Mali is occurrence of several infectious diseases. A particular challenge for control of pathogens that affect different species, especially in a system with mixed herds with cattle, sheep and goats. Therefore, this study aimed to investigate co-exposure with Rift Valley fever virus (RVFV), Coxiella burnetii, Bluetongue virus (BTV) and Brucella spp. in different livestock species in mixed herds. With the exception of BTV these pathogens are also zoonotic. A retrospective assessment was carried out on a biobank of sera of cattle and small ruminants collected from Sikasso and Mopti regions. Nine hundred and twelve samples from cattle (n = 304), sheep (n = 318) and goat (n = 290) were screened. Serology tests were conducted using commercial kits as per the protocol of the manufacturers. Sero-prevalence for RVFV was 12.8% (Confidence Interval 95%: 9.3–17.1%); 4.7% (2.7–7.7%) and 3.1% (1.4–5.8%) in cattle, sheep and goat respectively. For Coxiella burnetii, the sero-prevalence was 55.3% (49.5–60.9%), 22.6% (18.2–27.6%), and 16.9% (12.8–21.7%); in cattle, sheep and goat respectively; and for BTV sero-prevalence was 88.8% (84.72–92.13%), 51.6% (45.9–57.2%), 56.2% (50.3–62.0%) in cattle, sheep in goat respectively. Brucella sp. had the lowest sero-prevalence and was only detected in cattle and sheep. Regional differences were observed with sero-prevalence of Coxiella burnetii in sheep and goat with BTV in goat being significantly higher in Sikasso than in Mopti (p<0.001). Evidence of exposure to two pathogens in the same animal was most common for the combination Coxiella burnetii and BTV in cattle (51.6%), followed by sheep (17.0%) and goat (15.5%). Considering the scarcity of disease occurrence and epidemiological data in most sub-saharan countries including Mali, this multi-pathogen survey provides important evidence that cattle, sheep and goat are exposed to pathogens that may negatively impact productivity and pose a risk for public health. The results from this study highlight the urgent need for a better understanding of pathogen diversity and their impact on human and animal health in order to minimize resulting risks. Given that some of the pathogens investigated here are zoonotic, establishment of One-Health surveillance system to monitor disease in animals and people is warranted. Therefore, intersectoral collaboration is recommended. 相似文献
6.
C. Maudet A. Beja‐Pereira E. Zeyl H. Nagash A. Kence D.
züt M.‐P. Biju‐Duval S. Boolormaa D. W. Coltman P. Taberlet G. Luikart 《Molecular ecology resources》2004,4(1):49-55
Nearly 70% of the world's mountain ungulate taxa are endangered. The availability of a standard set of DNA markers for forensic and molecular ecology studies would help to establish conservation programs and detect poaching activities of these endangered taxa. We tested 60 published microsatellite primer pairs from bovids (cattle, sheep and goat) on 49 individuals from 11 taxa including six wild goat‐like species (Capra spp.), three divergent wild sheep (Ovis spp.), and two chamois (Rupicapra spp.) species. Approximately 30 microsatellites amplified a microsatellite‐like PCR product in all three genera, and with the exception of ILST097, nearly all the loci were polymorphic within most of the 11 species. 相似文献
7.
We cloned the cDNA and genomic DNA encoding for Izumo1 of cashmere goat (Capra hircus) and sheep (Ovis aries). Analysis of 4.6 kb Izumo1 genomic sequences in sheep and goat revealed a canonical open reading frame (ORF) of 963 bp spliced
by eight exons. Sheep and goat Izumo1 genes share >99% identity at both DNA and protein levels and are also highly homologous to the orthologues in cattle, mouse,
rat and human. Extensive cloning and analysis of Izumo1 cDNA revealed three (del 69, del 182 and del 217) and two (del 69
and ins 30) alternative splicing isoforms in goat and sheep, respectively. All of the isoforms are derived from splicing at
typical GT-AG sites leading to partial or complete truncation of the immunoglobulin (Ig)-like domain. Bioinformatics analysis
showed that caprine and ovine Izumo1 proteins share similar structure with their murine orthologue. There are a signal peptide
at the N-terminus (1–22 aa), a transmembrane domain at the C-terminus (302–319 aa), and an extracellular Ig-like region in
the middle (161–252 aa) with a putative N-linked glycosylation site (N205-N-S). Alignment of Izumo1 protein sequences among 15 mammalian species displayed several highly conserved regions, including
LDC and YRC motifs with cysteine residues for potential disulfide bridge formation, CPNKCG motif upstream of the Ig-like domain,
GLTDYSFYRVW motif upstream of the putative N-linked glycosylation site, and a number of scattered cysteine residues. These
distinctive features are very informative to pinpoint the important gene motifs and functions. The C-terminal regions, however,
are more variable across species. Izumo1 cDNA sequences of goat, sheep, and cow were found to be largely homologous, and the
molecular phylogenetic analysis is consistent with their morphological taxonomy. This implies the Izumo1 gene evolves from the same ancestor, and the mechanism of sperm–egg fusion in mammals may be under the same principle in
which Izumo1 plays an important role. 相似文献
8.
《Archives of animal nutrition》2013,67(5):412-417
Abstract Anaerobic ruminal fungi may play an active role in fibre degradation as evidenced by the production of different fibrolytic enzymes in culture filtrate. In the present study, 16 anaerobic fungal strains were isolated from ruminal and faecal samples of sheep and goats. Based on their morphological characteristics they were identified as species of Anaeromyces, Orpinomyces, Piromyces and Neocallimastix. Isolated Neocallimastix sp. from goat rumen showed a maximum activity of CMCase (47.9 mIU ml?1) and filter paper cellulase (48.3 mIU ml?1), while Anaeromyces sp. from sheep rumen showed a maximum xylanolytic activity (48.3 mIU ml?1). The cellobiase activity for all the isolates ranged from 178.0 – 182.7 mIU ml?1. Based on the enzymatic activities, isolated Anaeromyces sp. from sheep rumen and Neocallimastix sp. from goat rumen were selected for their potential of in vitro fibre degradation. The highest in vitro digestibility of NDF (23.2%) and DM (34.4%) was shown for Neocallimastix sp. from goat rumen, as compared to the digestibility of NDF and DM in the control group of 17.5 and 25.0%, respectively. 相似文献
9.
Mapping of mitochondrial DNA of individual sheep and goats: Rapid evolution in the D loop region 总被引:1,自引:0,他引:1
Mitochondrial DNA (mtDNA) from sheep and goat was compared by restriction endonuclease analysis and heteroduplex mapping in the electron microscope. The fragment patterns produced by endonuclease Hae III from three individual sheep and two goat mtDNAs all differed from each other. The three sheep mtDNAs had identical Eco RI and Hind III fragments, but the two goat mtDNA patterns differed from each other as well as from sheep mtDNA. We estimate that each sheep mtDNA differs from each other by 0.5–1% of its nucleotide sequences, the two goat mtDNAs by 1–2%, and there is a 6–11% sequence difference between sheep and goat mtDNAs. We have mapped the Eco RI and Hind III sites of goat and sheep mtDNA and determined the positions of the D loop, which marks the replication origin, relative to the restriction map. The D loops are at homologous positions on the mtDNAs from both species, but the goat D loop is only 75% as long as the sheep D loop. Regions with a high degree of sequence divergence occur at both ends of the D loop. We suggest that a duplication of about 150 base pairs has occurred in the region where the sheep and goat D loops differ in length. We discuss mtDNA evolution in terms of divergence of isolated “mitochondrial DNA clones.” 相似文献
10.
《Small Ruminant Research》2007,70(1-3):55-61
Five groups of 20 infested skins with different ectoparasites and different levels of infestation and two groups of negative control skins from sheep and goats were examined for their corresponding defects at the pickled or wet blue stage of processing in tanneries. In addition, an analysis of skin defects was made from randomly selected processed skins at Kombolcha and Dessei tanneries. The prevalence of ‘ekek’ (cockle) at the pickled stage in Damalina ovis and Melophagus ovinus-infested sheep skins were 100 and 95%, respectively. Pickled goat skins affected by sarcoptic mange and Linognathus spp. were 100 and 0% positive for ‘ekek’ (cockle) lesion, respectively. The prevalence in control sheep and goat skins were 15 and 0%, respectively. There was a strong association (p < 0.05) between ‘ekek’ and infestation with M. ovinus and D. ovis in sheep and sarcoptic mange in goats. Follow-up of randomly selected 1000 pickled sheep skins and 1000 wet blue goat skins revealed that 71% of pickled sheep and 42% of wet blue goat skins had ‘ekek’ lesions. As the proportion of ‘ekek’ increased, the quality of graded skins decreased both in sheep and goats. Both on pickled sheep and wet blue goat skins, scratch and scars were found to have a strong association (p < 0.05) with ‘ekek’. The annual economic loses in 2002/2003 due to ‘ekek’ at the two tanneries was estimated to be 1.6 million USD for pickled sheep and 0.6 million USD for wet blue goat skins. 相似文献
11.
Koichi Takahashi Shigeru Uemura Toshihiko Hara 《Landscape and Ecological Engineering》2011,7(1):101-108
The relationship between rain flow into the soil and forest structure was investigated in a dense deciduous Betula ermanii forest in northern Japan. The forest floor was covered with dwarf bamboo Sasa kurilensis. Observation was conducted from mid-July to late October in 1998. Leaf fall of Betula started in early September and ended in late October. Stemflow was proportional to rainfall and tree size [diameter at breast
height (DBH)], and for the same rainfall, stemflow increased with leaf fall. On the contrary, throughfall decreased with leaf
fall. Throughfall was intercepted also by Sasa in proportion to its leaf area. Multiple linear regression analysis revealed that stemflow and throughfall of Betula and Sasa were predictable as functions of rainfall and forest structural characteristics, such as DBH, tree density, and stand leaf
mass. The rain interception by plants tended to decrease from summer to autumn, but the difference in the interception was
about 2% between July (fully expanded leaves) and late October (lack of leaves). About 96 and 87% of rainfall reached the
above- and below-Sasa layers, respectively. Thus, this study showed that understory Sasa is a major component of rain interception within the stand and that rain flow into the soil can be estimated by using rainfall
and the forest structural parameters, such as DBH, tree density and stand leaf mass. 相似文献
12.
Céline Termote Gert Everaert Marcel Bwama Meyi Beno?t Dhed’a Djailo Patrick Van Damme 《Human ecology: an interdisciplinary journal》2012,40(2):269-285
Benefits from wild edible plants (WEP) are multiple for rural households as well as urban traders. To set species priorities
for WEP market development and domestication, we performed an inventory of WEP species and traders in five markets and one
road-side selling point in Kisangani. During four one-month sessions between September 2007 and July 2008, all WEP traders
present in the target markets were interviewed. We registered 119 unique sellers, selling 15 different WEPs. The September-October
period and ‘Marché Central’ were the most important for WEP trade in Kisangani. Added values and net incomes generated through
WEP sales were very divergent. Four types of traders could be distinguished. Gnetum africanum trade involves the more dynamic traders. Cola acuminata, Garcinia kola and Piper guineense spices have local and international market potential. Within the wild fruits category we propose Landolphia owariensis and Tetracarpidium conophorum as priority species for local market development. 相似文献
13.
Benzidine staining of starch gels after electrophoresis of sera to which haematin was added revealed polymorphism of haemopexin in sheep, mouflon and goat. In sheep three phenotypes were observed, Hpx A, Hpx AB and Hpx B. Pedigree data support the hypothesis of codominant inheritance from a single locus by two alleles, HpxA and HpxB. Neuraminidase treatment of haemopexin preparations showed that Hpx B covered two variants, B1 and B2, thus indicating genetic control by three alleles (HpxA, HpxB1 and HpxB2). In sheep populations the frequency of HpxB is low. In mouflon, in addition to the two variants that are like those of sheep, absence of haemopexin was observed in some animals, by using starch gel electrophoresis as well as immunoelectrophoresis. In goat, three phenotypes were detected, Hpx A, Hpx AB and Hpx B, differing in migration from those of sheep. Haemopexins of the studied species are heterogeneous. Sialic acid is responsible for electrophoretic heterogeneity of sheep haemopexin. Chemical. composition (amino acid and carbohydrate), molecular weight (56 060) and N-terminal sequence (Leu-Pro-Pro-) of sheep haemopexin were also determined. 相似文献
14.
15.
Granar Marie IKS Nilsson Bo R Hamberg-Nyström Helene L 《Acta veterinaria Scandinavica》2011,53(1):1-9
Background
Anthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR), representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway.Methods
A questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3%) and 238 goat flocks (52.6%) were included.Results
The results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6%) and goat (85.1%) flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year) in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007), whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks.Conclusions
The present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of anthelmintic resistance (AR) seems to exist in Norwegian sheep and goat flocks. This risk seems particularly high in coastal areas where high treatment frequencies in lambs were recorded. 相似文献16.
Abstract A method is described for developing a sheep‐ vs. goat‐specific DNA marker using sequence characterized amplified regions (SCARs) derived from a random amplified polymorphic DNA (RAPD) marker from sheep DNA samples. A sheep 645 bp DNA fragment that was absent in goat DNA was identified by analyzing pools of sheep and goat DNA with RAPD primers. This fragment was cloned and partially sequenced to design extended, strand‐specific 24‐mer oligonucleotide primers. Each primer contained the original 10 bases of the RAPD primer and the following 14 internal bases. The pair of primers resulted in the amplification of a single band of 645 bp when used to amplify sheep DNA, and in no amplification when used to amplify goat DNA. These SCAR primers successfully amplified the equivalent of DNA from one nucleated sheep cell in a sample of 5000 nucleated goat cells. This level of sensitivity is especially desirable for research involving the detection of interspecific chimerism. 相似文献
17.
Henn M 《EMBO reports》2011,12(4):296-301
Speculators increasingly invest into food markets for financial gain, with potentially devastating consequences for millions of poor people who cannot afford food at inflated prices....the market price of agricultural commodities is more important than those of nearly all other productsMost citizens in developed countries buy and consume their food without any consideration of how it is produced or how it gets from the field or slaughterhouse to the supermarket. They take for granted that they can afford it and do not care about its production and the economic, financial and other factors that eventually determine its price on the supermarket shelf. However, the market price of agricultural commodities is more important than those of nearly all other products. Increasing prices can cause hunger for millions of people and enormous political repercussions. In 2007–2008, a price explosion for grain and other commodities caused malnutrition among an estimated 115 million people and triggered hunger revolts in several nations. The prices subsequently dropped, only to soar again three years later (Fig 1), surpassing previous highs by the end of 2010. The revolt in Tunisia in January 2011 that eventually led to the government''s downfall was originally triggered by rising food prices.Open in a separate windowFigure 1FAO Food Price Index values from 1990 to 2010“The FAO Food Price Index is a measure of the monthly change in international prices of a basket of food commodities. It consists of the average of five commodity group price indices (representing 55 quotations), weighted with the average export shares of each of the groups for 2002–2004” (http://www.fao.org). FAO, Food and Agricultural Organization.Which factors or mechanisms determine the market price of food? If a drought or a flood were to destroy harvests in wheat-exporting countries such as Australia or Russia, it would certainly drive up the price of wheat. Yet, there is also ongoing debate about whether and how the 2007–2008 price spike might have been driven by financial speculation in commodity markets. This is not only a media debate, but also of scientific interest as it gets to the heart of economic theory; indeed, various research articles have tried to analyse and explain the causes of the 2007–2008 price spike.The revolt in Tunisia in January 2011 that eventually led to the government''s downfall was originally triggered by rising food pricesThe global market-prices for agricultural commodities are determined in different ways, depending on the commodity. Some products, such as rice, are mainly traded nationally, with only a small share being traded internationally; other commodities are traded in large quantities on international commodity exchanges, particularly in the USA. As the USA is one of the main producers and exporters of wheat, corn and soybean—and has a liberal market tradition—these exchanges are important for both the US and the global agricultural industry. In Europe, commodity exchanges for agricultural products play a lesser role, partly owing to the former Common Agricultural Policy of the European Union (EU), which tightly regulated the production of foodstuffs. However, this policy is now changing and exchanges are set to have a more important role in Europe too. The Paris commodity exchange is already a relevant marketplace for wheat, and the London commodity exchange has an important role in the global trade of coffee, cocoa and sugar.The price of any commodity should reflect the levels of supply and demand. Of course, fluctuations occur and are sometimes justified by fundamental factors, for example a bad harvest or increased demand. However, other external factors—such as a lack of information, asymmetries, externalities, conflicts of interest and agency problems—can also influence prices on commodity markets. In addition, outright speculation (for instance by hoarding), price bubbles and even market manipulation can repeatedly influence prices. The largest grain companies in the world, such as ADM, Cargill, Dreyfus and Bunge, have an interest in maximizing their profits and do so by buying and selling commodities at the most suitable time. Even farmers speculate on commodity markets, for example by withholding their harvest when they expect a price rise. To keep these factors and interests under control it is necessary and indeed legitimate to regulate and control markets, not just for food commodities.Commodities are not only traded physically on ‘spot'' or cash markets, but also subject to forward buying through ‘futures''. A future is a contract between a producer—that is, a farmer—and a buyer that specifies the amount, the price and the delivery date of a purchase. Similarly, buyers—such as millers—can use futures to buy a certain amount of grain at a guaranteed price ahead of time. Many farmers and end-users take advantage of futures to pre-sell or pre-purchase agricultural goods to insure themselves against market fluctuations. This ‘hedging'' reduces their risks and enables them to invest more safely.Intermediary traders ensure that the two sides meet. Traditionally, these traders are established firms that buy and sell futures from producers and to consumers, thereby providing the necessary liquidity. They shoulder the risks and gain their profits from the difference between the price stipulated in a future and the final market-price. These firms, naturally, have a profound knowledge and understanding of the commodity markets in which they are trading.In addition, such trading can take place both on exchanges (then called ‘futures trading'') and bilaterally ‘over-the-counter'' (OTC). Modern trading in commodity futures began in the USA during the mid-nineteenth century. Chicago, where the first modern wheat futures were traded, is still the largest and most important marketplace for agricultural commodities in the world, even though Asian countries have contested this in recent years.As futures no longer require the seller to possess the actual goods and because physical delivery is replaced by cash exchanges, their volume can be separated from the actual quantity of the commodity; their volume can also increase indefinitely as long as enough intermediaries want to deal with them. In the past, though, relatively few investors and intermediaries speculated on future markets. Moreover, regulatory agencies can and have imposed rules to limit the extent of speculation, for instance by regulating delivery dates, delivery locations, the timeframe for buying, certified stocks, storage fees, position limits, price limits and other factors.However, an increasing number of investors from outside the traditional markets—including banks, and pension and investment funds—have begun to speculate on agricultural futures exchanges. These large investors not only push the exploitation of price trends, but also—in contrast to the traditional intermediaries—are often not familiar with the cash market and the fundamentals. These outside speculators also often invest for reasons that have nothing to do with the cash market, for instance to protect themselves against price fluctuations on financial markets....an increasing number of investors from outside the traditional markets—including banks, and pension and investment funds—have begun to speculate on agricultural futures exchangesThis is the main reason that the US government imposed strict limits for financial speculation on commodity future exchanges. Only commercial participants with an interest in hedging were exempted. However, these rules and limits have been slowly eroded or removed. In 1991, one financial investor managed to get an official exemption from the limits in order to hedge his financial risk. In the following years, more traders were granted such exemptions or limit expansions. In 2000, the Commodity Futures Modernization Act exempted OTC trading from regulatory oversight and control. As a result of laxer oversight, other speculators joined the market, especially after the beginning of the financial crisis in 2006. These newcomers include banks such as Goldman Sachs, JP Morgan and Deutsche Bank; pension funds, such as the California State Teachers'' Retirement System; and hedge funds. A good deal of their trading is carried out through ‘swaps'', a type of OTC instrument.As these new and powerful speculators have entered the market, the total volume of new speculative investments in commodity indexes has increased more than tenfold in five years...As these new and powerful speculators have entered the market, the total volume of new speculative investments in commodity indexes has increased more than tenfold in five years: from an estimated $15 billion in 2003 to around $200 billion in 2008. ‘Index funds'', which aim to imitate the cash markets with futures, rose particularly high: between 2006 and 2008, index traders increased the demand for wheat futures from 33% to 100%. The number of daily outstanding contracts held by index traders on the Chicago Mercantile Exchange grew from approximately 30,000 in early 2004 to 220,000 in mid-2008 (US Senate PSI, 2009).The unexpected price hike in 2007–2008 has triggered a lively debate among economists about whether this increased speculation in futures has driven up cash prices. This discussion is both a theoretical debate about how futures markets work and an empirical debate about the reasons behind the price rise. The main questions are: Can speculation alone move the prices of futures and can there be excessive, that is, harmful, speculation in futures? Can futures prices influence the cash markets, and if so, how?Some claim that that the amount of trading in futures is irrelevant to the real price, because it is always a “zero-sum game” between traders (Irwin & Sanders, 2010). For every position that bets on a rising price (long position), there is a counterparty which bets on a falling price (short position). By this view, the amount of trading is detached from the price level. Indeed, it is not possible to demonstrate an unequivocal relationship between the amount of trading and the price.Yet, a large in-flow or out-flow of money can create a price shift. Statistical research has demonstrated the growing interdependence of commodity markets, both between the markets themselves and with financial markets. Tang & Xiong (2010) found that “concurrent with the rapidly growing index investment in commodities markets since the early 2000s, futures prices of different commodities in the US became increasingly correlated with each other. [...] In contrast, such commodity price co-movements were absent in China, which refutes growing commodity demands from emerging economies as the driver.”Silvennoinen & Thorp (2010) observe, “higher and more variable correlations between commodity futures and stock returns.” This trend—often called financialization—has also been observed by the United Nations Conference on Trade and Development (UNCTAD, 2009; Mayer, 2009). Similarly, an investigation by the US Senate took the view that the price of US futures had been influenced by excessive speculation (US Senate PSI, 2009).The second question, which is more relevant to consumers, remains: how can futures prices influence the cash price? Theoretically, the cash price should always converge with the futures price once the future is delivered. Some economists therefore assume that if futures are over-priced, the cash market will simply solve this problem by speculative arbitrage trading: buying something at a lower price and immediately reselling it for a higher price. Futures markets, in this view, are always driven by the cash markets, which themselves are determined by the fundamental mechanisms of supply and demand (Irwin & Sanders, 2010). However, it is logical to assume that futures markets have an influence on cash markets because, as all economists agree, they should predict the future price on the cash markets.Thus: how does speculation in futures influence prices on cash markets and how long does the effect last? Some scientists at the UN Food and Agricultural Organization were able to identify only short-term effects (Dreschler et al, 2010), but what does short-term mean? Different economists use different definitions: some define short-term as one day, others one week and some others one month. However, if the same effect leads to a one-month deviation, why should it not cause a deviation of many months? And what is the effect of a month-long deviation for people who need to buy food every day? As the famous economist John Maynard Keynes noted, in the long run we are all dead. Indeed, financial speculators cannot suspend the laws of supply and demand in the long-term, but they are able to cause short- to medium-term price increases, which, for the world at large, is bad enough.Traders are usually open about the effects of their trading. In April 2006, a hedge fund manager commented: “There is so much money going into commodity markets that it almost doesn''t matter how fundamentals behave” (WDM, 2010). At the same time, the investment bank Merill Lynch estimated that commodity prices had increased by 50% through speculation (Thornton, 2006). One of the most well-known speculators, George Soros, commented that, “Every speculation is also rooted in reality [however] speculators create the bubble that lies above everything. Their expectations, their gambling on futures help drive up prices, and their business distorts prices, which is especially true for commodities. It is like hoarding food in the midst of a famine, only to make profits on rising prices. That should not be possible” (WDM, 2010).Furthermore, if the futures price is higher than the cash price, traders on the cash market are inclined to store food in order to gain higher incomes. This is a common occurrence in hard commodity markets, such as oil or metal. However, hoarding of agricultural commodities driven by expectations of higher prices can also take place. Finally, divergent cash and futures prices, along with market volatility, cause other problems; higher costs are required for risk management and hedging, which harms the food business and ultimately affects food supply and prices (US Senate PSI, 2009).Many observers initially argued that the price spike of 2007–2008 was related to bad harvests, rising demand from importing countries—notably China—and the growing production of biofuels. A leading study by the World Bank was perhaps most influential at the time (World Bank, 2008). However, even when it became clear in early 2008 that harvests had recovered, the prices still rose. Moreover, prices on the cash and futures markets plummeted from mid-2008 onwards although demand from emerging countries remained high, even during the financial crisis. Some researchers are still not convinced that the 2007–2008 price spike was caused by speculation and continue to point to the increasing demand for biofuels, depreciation of the US dollar and the rising price of oil to explain this phenomenon (Headey & Fan, 2010).Nonetheless, criticism of financial speculations on commodity markets has been growing. In 2009, US hedge fund manager Michael W. Masters testified to the US Senate that passive investment, such as index funds, “provides no benefits to the markets while it exacts a heavy toll” (Masters, 2009). Accordingly, the US Senate and various scholars found signs of excessive and harmful speculation in US wheat markets (US Senate PSI, 2009; Lines, 2010; Gilbert, 2010). Headey & Fan (2010) reject the argument that rising demand from emerging countries could have caused the spike, writing that “low interest rates, and investment portfolio adjustments in favour of commodities” have an important role in price formation. The World Bank, in a recent working paper (Baffes & Haniotis, 2010), has also recognized the influence of financial speculators on prices: “We conjecture that index fund activity [...] played a key role during the 2008 price spike. Biofuels played some role too, but much less than initially thought. And we find no evidence that alleged stronger demand by emerging economies had any effect on world prices.” In a more recent paper by the UN Special Rapporteur on the Right to Food, Olivier de Schutter (2010) found that “a significant portion of the price increases and volatility of essential food commodities can only be explained by the emergence of a speculative bubble.”Another reason to assume that speculation is a harmful influence is that the oil-price peak of 2008 also seems to have been caused by speculation (Masters, 2009; Chevalier et al, 2010). This is not an independent explanatory variable for the price rise in agricultural commodities, but it highlights the impact of speculation.In addition to index funds, hedge funds have become increasingly important players in commodity markets. These funds, which can invest more freely than any other type of fund, often take highly speculative long and short positions to profit from rising or falling prices. Hedge funds can also move huge amounts of money. In July 2010, a single hedge fund bought almost all cocoa futures on the London commodity exchange, in an attempt to force cocoa buyers to buy from it at a monopolistic price. Afterwards, a group of cocoa processing companies called on the London International Financial Futures and Options Exchange to prevent such speculations and threatened to go to the New York commodity exchange, where tighter regulations are in force.Today, there is again a debate about whether speculation has a role in rising prices. On the one hand, harvest losses for wheat crops in July 2010 would justify a slight price rise. On the other hand, National Farmers Union representative Doug Sombke said at a US Commodity Futures Trading Commission hearing in the USA, “I think speculators have created a huge mess here for us. Farmers are feeling this today” (Reuters, 2010). Klaus Josef Lutz, CEO of BayWa, one of Europe''s biggest grain traders, commented that, “70 percent of the price rise can be blamed on speculators” (Handelsblatt, 2010). Finally, wheat is not nearly as scarce as the price rise would suggest: the global 2010 harvest is estimated to be the third largest of all time (FAO, 2010a).Higher food prices not only cause immediate problems; by reducing the available money for health care and education, they also produce negative long-term effectsTwo-thirds of developing countries are net importers of basic food commodities, even if the percentage of farmers in these countries is much higher than in industrialized countries. Furthermore, the relative household expenditure on food is much higher in developing countries: 60–80% compared with approximately 15% in the EU. This makes developing countries particularly vulnerable to price rises. They were hit hard in 2007–2008 and are again facing serious problems; the recent revolt in Tunisia being the most visible uprising sparked by food prices. Higher food prices not only cause immediate problems; by reducing the money available for health care and education, they also produce negative long-term effects.Some developing countries are commodity producers. As such, they profit, more or less, from price increases. However, their small-scale farmers are the weakest link in the production chain and profit the least from price rises. Apart from speculators, it is larger intermediaries, retailers or bigger farms that reap most of the profits (Höffler & Owour Ochieng, 2009).Growing ‘financialization'' makes it vital to reform commodity futures markets and set clear limits for speculation. Trading by financial speculators must take place on regulated and transparent commodity exchanges. The number and influence of speculators must be controlled through market and position limits. As Ann Berg, former commodity trader, stressed at a recent FAO special committee, “Over 150 years of futures trading history demonstrates that position limits are necessary in commodities of finite supply to curb excessive speculation and hoarding” (FAO, 2010b). Furthermore, some types of investment, such as index funds, could be strongly restricted. Generally, a legal demarcation between the commodities futures markets and the financial markets and a special agency to oversee it is required, such as the US Commodity Futures Trading Commission.The USA has learned its lesson from the past few years and is once again restricting financial speculation through reforms introduced in July 2010The USA has learned its lesson from the past few years and is once again restricting financial speculation through reforms introduced in July 2010. The US government aims to return OTC trading—mostly carried out as swaps—to multilateral trading and clearing platforms. Higher transparency requirements will apply and financial speculators will once again be limited by stricter position limits, without exemptions.As mentioned above, fewer agricultural commodities are traded on a large scale in the EU, but the London and Paris commodity exchanges still exert an influence. Moreover, stricter regulations in the USA could induce speculators to move their activities to European exchanges, even though there are strong position limits, at least at the Paris commodity exchange. Reforms of the financial markets in the EU are therefore necessary, and these are currently being debated. Michel Barnier, the European Commissioner for Internal Market and Services, has rightfully called speculation with food commodities a scandal. Whether his words will be followed with actions remains to be seen.In September 2010, the European Commission released draft regulations for OTC derivatives that include plans to create new trading platforms called ‘central counterparties''. The draft regulations require that OTC trades are limited and fulfil transparency requirements (EC, 2010). Along with these, two other directives will be revised: one on markets in financial instruments, such as futures, and one on market abuse. However, the EU has not yet acknowledged that commodities markets are not the same as financial markets. It is therefore not certain whether they will propose and pass appropriate regulation, which ought to include a special regulatory body, full transparency and position limits....farmers and buyers have a strong interest in managing their risks, and futures markets have proven to be an appropriate, if imperfect, mechanism...Given the problems that commodity futures markets have caused, it might be tempting to renounce them. Conversely, farmers and buyers have a strong interest in managing their risks, and futures markets have proven to be an appropriate, if imperfect, mechanism by which to do so. Other measures such as harvest assurances bring their own disadvantages. Moreover, local markets can also cause problems, as can political measures, especially when these include export bans.Nonetheless, it is prudent to explore alternatives. These could include regional or bilateral treaties between states, which have been successfully practised in several cases in Asia. The build-up of higher, more reliable reserves at the national, regional or global level is another option for dealing with volatility and uncertainty. Such reserves could also be virtual, as has been suggested by one leading agricultural researcher, Professor Joachim von Braun from Bonn University in Germany (von Braun, 2010).In the meantime, banks and hedge funds have also begun to invest in cash markets. In 2009, Goldman Sachs, Barclays and JP Morgan reportedly controlled physical commodities worth £16 billion—more than three times the amount they controlled in 2008. The head of one cocoa retail company commented on this development: “A lot of branch-alien money has poured into the market. The banks that are part of the game now are not giving us loans anymore or require much more collateral, as the markets have become more volatile. This is really grotesque” (Handelsblatt, 2010). This seems to be the next step in the ‘financialization'' of commodity markets, but the central question is whether banks should be able to buy our food or if they should get back to their initial purpose: serving the economy with credit.Food markets should serve the interests of people and not those of financial investorsFood markets should serve the interests of people and not those of financial investors. In this regard, politics has failed to protect food markets from excessive speculation. As former US President Bill Clinton said in a speech at the United Nations'' World Food Day on 16 October, 2008, “We need the World Bank, the IMF, all the big foundations, and all the governments to admit that, for 30 years, we all blew it, including me when I was President. We were wrong to believe that food was like some other product in international trade, and we all have to go back to a more responsible and sustainable form of agriculture” (Clinton, 2008).Given that hunger still exists in the world, even small price increases that are driven by financial investment are scandalous. We must not allow food to become a purely financial asset.?
Open in a separate windowMarkus Henn
Science & Society Series on Food and Science
This article is part of the EMBO reports Science & Society series on ''food and science'' to highlight the role of natural and social sciences in understanding our relationship with food. We hope that the series serves a delightful menu of interesting articles for our readers. 相似文献18.
Different percentages of cells with a female sheep or male goat karyotype were found in kidney (12.0% vs. 88.0%) and lung (42.6% vs. 57.4%) cell cultures from a 10-year-old chimera. Skin biopsies from patches with goat hair or sheep wool showed different, age-related goat-to-sheep fibroblast ratios. Karyotypic analysis of lymphocytes obtained from peripheral blood of the chimera at 6 and 10 yr of age showed no chimerism. Two weeks after birth, however, lymphocytes with both sheep (54,XX) and goat (60,XY) karyotypes were apparent in the blood of this chimera. Twenty percent of the blood cells examined at 2 wk had a caprine karyotype; this proportion declined with time, until it was totally eliminated at age 6. 相似文献
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Shubham Goyal Praveen K. Dubey Kabita Tripathy Ritu Mahajan S. Pan S. P. Dixit 《Animal biotechnology》2013,24(3):194-203
In this study, approximately 3.4 kb nucleotide sequence of caprine TLR7 (Toll-like receptor 7) gene was generated from twelve different Indian goat breeds belonging to different geographical regions. Goat TLR7 gene ORF (Open Reading Frame) was found to be 3141 nucleotides long coding for 1046 amino acids similar to sheep. The sequence analysis at nucleotide level revealed goat TLR7 having 99.5% homology with sheep, followed by other livestock species. Simple Modular Architecture Research Tool (SMART) was used for the structural analysis of goat TLR7 that showed the presence of 22 leucine rich repeats (LRRs) along with single Toll/interleukin-1 receptor (TIR) domains. TIR domain, when compared, was found to be similar in ruminant species, goat, sheep, cattle, and buffalo. The phylogenetic analysis also revealed grouping of all ruminant species together, goat being closer to sheep followed by cattle and buffalo. A total of 22 polymorphic sites were observed in TLR7 gene of 24 goats representing 12 different breeds, out of which 19 were present within the coding region and three in 3'UTR. Out of the seven nonsynonymous SNPs, two were in ectodomains and one in TIR domain. Overall our results indicate substantial variation within goat TLR7 gene, which could be exploited for association with disease susceptibility. 相似文献
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During anemic episodes, goats and certain sheep replace hemoglobin A (HbA = α2β2A) with hemoglobin C (HbC = α2β2C). Rabbit serum directed against either purified sheep HbA or purified sheep HbC was prepared. Both types were used to test whether the two hemoglobins are found in the same cell during switching by an indirect fluorescent antibody assay.Unabsorbed antisheep HbA cross-reacted extensively with goat HbA but to a lesser extent with goat or sheep HbC. Similarly, unabsorbed antisheep HbC reacted with these antigens in the order: Sheep HbC > goat HbC > sheep HbA > goat HbA. Cross-absorption resulted in sera specific either for sheep and goat HbA or for sheep and goat HbC. The specificities were confirmed by indirect fluorescent antibody staining of sheep and goat erythrocytes containing either at least 99% HbA or at least 99% HbC.Smears of erythrocytes from sheep and goats in the process of switching were reacted with one of the absorbed sera then with fluorescein conjugated antirabbit immunoglobulin G. The sum of the fractions stained both by anti-HbA and by anti-HbC exceeded 100% during the switch. Most strikingly when HbA was replacing HbC, nearly all cells stained for HbC while more than half stained for HbA. Thus, the two hemoglobins are found in the same cell during switching. 相似文献