Home About us Contact
|
Home About us Contact | ||
|
|
||
Livestock Production (livestock + production)
Selected AbstractsClimate change and the characterization, breeding and conservation of animal genetic resourcesANIMAL GENETICS, Issue 2010Irene Hoffmann Summary Livestock production both contributes to and is affected by climate change. In addition to the physiological effects of higher temperatures on individual animals, the consequences of climate change are likely to include increased risk that geographically restricted rare breed populations will be badly affected by disturbances. Indirect effects may be felt via ecosystem changes that alter the distribution of animal diseases or affect the supply of feed. Breeding goals may have to be adjusted to account for higher temperatures, lower quality diets and greater disease challenge. Species and breeds that are well adapted to such conditions may become more widely used. Climate change mitigation strategies, in combination with ever increasing demand for food, may also have an impact on breed and species utilization, driving a shift towards monogastrics and breeds that are efficient converters of feed into meat, milk and eggs. This may lead to the neglect of the adaptation potential of local breeds in developing countries. Given the potential for significant future changes in production conditions and in the objectives of livestock production, it is essential that the value provided by animal genetic diversity is secured. This requires better characterization of breeds, production environments and associated knowledge; the compilation of more complete breed inventories; improved mechanisms to monitor and respond to threats to genetic diversity; more effective in situ and ex situ conservation measures; genetic improvement programmes targeting adaptive traits in high-output and performance traits in locally adapted breeds; increased support for developing countries in their management of animal genetic resources; and wider access to genetic resources and associated knowledge. [source] Policies, Interventions and Institutional Change in Pastoral Resource Management in Borana, Southern EthiopiaDEVELOPMENT POLICY REVIEW, Issue 4 2004Abdul B. Kamara The Borana rangelands of Southern Ethiopia are characterised by extensive livestock production under a communal land-use system that has evolved in response to variable rainfall and uncertain production conditions. However, the last two decades have witnessed an increasing privatisation of rangelands for crop production and private grazing. The results of a quantitative assessment are used to develop a framework for assessing the drivers of change and their long-term implications. It is concluded that certain national policies have resulted in conflicts of authority between traditional and formal systems, creating an avenue for spontaneous enclosures, associated conflicts and decreasing human welfare. [source] Seasonal changes in herbage mass and nutritive value of a range of grazed legume swards under Mediterranean and cool temperate conditionsGRASS & FORAGE SCIENCE, Issue 3 2007U. Sölter Summary Seasonal changes in herbage mass and herbage quality of legume-based swards under grazing by sheep or cattle were investigated at four locations in climatically different zones of Europe: Sardinia (Italy), southern France, northern Germany and south-west England (UK). At each location standard treatments were applied to legumes typical of species widely used in each locality: Medicago polymorpha in Italy, Medicago sativa in France, and Trifolium repens in Germany and in UK. At each site comparisons were made of two other legumes: Trifolium subterraneum and Hedysarum coronarium in Italy, Onobrychis sativa and Trifolium incarnatum in France, Trifolium pratense and Lotus corniculatus in Germany, and Trifolium ambiguum and L. corniculatus in UK. Legumes were sown in mixture with locally appropriate companion grasses, and measurements were made over two or three grazing periods. In Italy M. polymorpha swards gave the greatest herbage mass in grazing period 1 but H. coronarium was more persistent. At the French site all legumes established poorly with no significant herbage mass differences between treatments. At both the UK and German sites L. corniculatus maintained a high proportion of legume in the sward; T. repens showed poor persistence under continuous sheep grazing in UK but persisted under cattle grazing in Germany, while T. ambiguum was slow to establish in the UK, and T. pratense proved to be of comparable herbage mass to the standard T. repens -based sward in the last year of the experiment. The concentration of crude protein and in vitro digestibility of organic matter in the dry matter of herbage showed greater within-season variation than between treatments at each site. It is concluded that, in addition to currently used species, legume-based swards containing H. coronarium, O. sativa and L. corniculatus all have potential to contribute to forage production for low-input grazing and their use merits further consideration in systems of livestock production in Europe. [source] Model predicting dynamics of biomass, structure and digestibility of herbage in managed permanent pastures.GRASS & FORAGE SCIENCE, Issue 2 2006Abstract To investigate seasonal and annual interactions between management and grassland dynamics, a simple mechanistic model of the dynamics of production, structure and digestibility in permanent pastures was constructed. The model is designed to respond to various defoliation regimes, perform multiple-year simulations and produce simple outputs that are easy to use as inputs for a model of ruminant livestock production. Grassland communities are described using a set of average functional traits of their constituent grass groups. The sward is subdivided into four structural compartments: green leaves and sheath, dead leaves and sheath, green stems and flowers, and dead stems and flowers. Each compartment is characterized by its biomass, age and digestibility. Only above-ground growth is modelled, using a light-utilization efficiency approach modulated by a seasonal pattern of storage and mobilization of reserves. Ageing of plant parts is driven by cumulative thermal time from 1 January and by biomass flows. Age affects senescence, abscission and digestibility of green compartments and, therefore, the quality of green leaves and stems can increase or decrease over time in relation to net growth and defoliation dynamics. The functional traits having the greatest impact on model outputs are seasonal effects, period of reproductive growth and effects of temperature on photosynthetic efficiency. The functional traits of the grass groups were parameterized for temperate pastures of the Auvergne region in France. The other model inputs are few: proportion of functional groups, basic weather data (incident photosynthetically active radiation, mean daily temperature, precipitation and potential evapotranspiration) and site characteristics (nitrogen nutrition index, soil water-holding capacity). In the context of a whole-farm simulator, the model can be applied at a field scale. [source] Consequences for biodiversity of reducing inputs to upland temperate pastures: effects on beetles (Coleoptera) of cessation of nitrogen fertilizer application and reductions in stocking rates of sheepGRASS & FORAGE SCIENCE, Issue 2 2004P. Dennis Abstract Current policies for upland pasture management in the UK encourage the integration of environmental objectives with livestock production through extensification of grazing systems. This study tested the hypothesis that a greater sward height in the summer would increase the diversity and abundance of grassland beetles (Coleoptera) as has been demonstrated for insects of indigenous grasslands. The hypothesis was tested with an experiment on an upland sheep pasture in mid-Wales. Experimental treatments received different nitrogen fertilizer inputs (0 or 50 kg ha,1), sheep stocking densities (12 or 9 ewes ha,1) and average sward heights in summer were constrained to 3·5 or 5·5 cm by conserving surplus grass for silage in subplots. Five treatments, replicated in three randomized blocks, combined the two stocking densities and two sward heights without nitrogen fertilizer inputs, with the fifth combining the higher stocking density, shortest sward height and the nitrogen fertilizer input. Beetles were sampled with twelve pitfall traps in each of the fifteen plots from June to September in 1993 and 1995. In years 1 (1993) and 3 (1995) of the experiment, more Coleoptera species occurred in the tall sward (an average of nine species in addition to the forty-one species present in the sward with the conventional sward height). Continuously grazed as opposed to ensiled subplots supported more beetle species but fewer individuals. Species composition of ground (Carabidae) and rove (Staphylinidae) beetles varied between treatments more than the arithmetic differences in species number. The experimental results supported the hypothesis but the benefits of taller swards to species diversity were small in the sown pastures of the study compared with indigenous upland grasslands (c. 33% fewer species). Inheritance effects of drainage, fertilizer and lime inputs, and the different species and management of cultivated pastures, may constrain the conservation benefits of altered pasture management compared with indigenous grasslands. [source] Conservation of forage resources for increasing livestock production in traditional forage reserves in TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 2008A. J. Mwilawa Abstract Traditional reserved pastures namely ,Olopololi/Alalili' for Maasai, ,Ngitili' for Sukuma and ,Milaga' for Gogo have been in use among the pastoral and agropastoral communities for many years. These reserves provide dry season feed for ruminant livestock especially cattle, sheep and goats. Apart from the provision of forage materials, these reserves provide fuel wood, construction material and medicinal plants. These traditional forage conservation practices also contribute to soil conservation and forage species biodiversity. However, studies conducted in these traditional forage reserves at Tingatinga (Maasai), Makang'wa (Gogo) and in Mwamishali/Mwanyanhina (Sukuma) in Tanzania show limitations of the reserves especially, in providing adequate dry matter and proteins for both maintenance and production of livestock. Nevertheless, there are opportunities for improvement on these traditional practices through introduction of improved grasses, legumes and tree/shrub species as well as proper maintenance of the superior local species and cultivars. [source] China's booming livestock industry: household income, specialization, and exitAGRICULTURAL ECONOMICS, Issue 6 2009Allan N. Rae China; Livestock industry; Specialization; Exit Abstract China's production of livestock products has generally kept pace with her rapidly increasing demand. Over-supply and market corrections for various livestock products took place over the latter part of the 1990s and large numbers of householders exited this type of production. Using household survey data, we estimate the relationship between a household's specialization in livestock production and household net income in 1995, and use a logit model to explore some predictors of household exit from livestock production over the following decade of market instability. We conclude that specialist livestock households with access to necessary skills, technologies, and markets increase their incomes from further livestock specialization in the base year, whereas those to whom livestock production is relatively unimportant can increase household incomes by diverting their resources away from animal husbandry. It was specialist rather than diversified livestock households that tended to bear the brunt of the adjustment to unfavorable price movements over the decade post-1995. Policy concerns include the exit of larger-scale specialized producers who tended to earn relatively high household incomes in 1995, barriers to the effective formation and operation of horizontal and vertical integration options to help mitigate market instability, the further development of insurance programs and markets for livestock producers, and development assistance to livestock households that for various reasons cannot increase scale and specialization. [source] Genetic approaches and technologies for improving the sustainability of livestock production,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004Stephen C Bishop Abstract Livestock production industries worldwide face considerable conflicting challenges and pressures. In developed countries the challenge is to remain sustainable and competitive in the face of declining prices and increasing costs, competition and public pressures. In developing countries the strong increase in demand for livestock products must be met in circumstances where infrastructure is often minimal, there are limitations on inputs and the environment places demands on management and on the adaptive fitness of the livestock. In both situations, solutions to these problems must be sustainable and appropriate, yet be technically feasible, cost-effective and publicly acceptable. This paper summarises the impact of two technologies that will make considerable contributions to sustainable livestock production systems, namely information technology and genetic technologies that utilise naturally occurring genetic variation. Genetic technologies are inherently sustainable owing to the permanent and cumulative nature of genetic change, and range from simple to sophisticated. They include breed choice, within-breed selection and the use of genetic markers linked to gene variants conferring favourable attributes. Breeding goals include increased output, where required, enhanced product quality and increased disease resistance. These goals are illustrated by examples for the hill sheep and pig sectors in the UK and by challenges facing animal health in developing countries. Central to all examples is the gathering, management and interpretation of information, ie information technology, which enables rational genetic and management decisions to be made. Additionally, in all sustainable livestock production systems the maintenance and utilisation of biodiversity will help manage the risks of today as well as the challenges of the future. Copyright © 2004 Society of Chemical Industry [source] The REFLECT Statement: Methods and Processes of Creating Reporting Guidelines for Randomized Controlled Trials for Livestock and Food SafetyJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010A.M. O'Connor The conduct of randomized controlled trials in livestock with production, health, and food-safety outcomes presents unique challenges that might not be adequately reported in trial reports. The objective of this project was to modify the CONSORT (Consolidated Standards of Reporting Trials) statement to reflect the unique aspects of reporting these livestock trials. A 2-day consensus meeting was held on November 18,19, 2008 in Chicago, IL, to achieve the objective. Before the meeting, a Web-based survey was conducted to identify issues for discussion. The 24 attendees were biostatisticians, epidemiologists, food-safety researchers, livestock production specialists, journal editors, assistant editors, and associate editors. Before the meeting, the attendees completed a Web-based survey indicating which CONSORT statement items would need to be modified to address unique issues for livestock trials. The consensus meeting resulted in the production of the REFLECT (Reporting Guidelines for Randomized Control Trials) statement for livestock and food safety and 22-item checklist. Fourteen items were modified from the CONSORT checklist, and an additional subitem was proposed to address challenge trials. The REFLECT statement proposes new terminology, more consistent with common usage in livestock production, to describe study subjects. Evidence was not always available to support modification to or inclusion of an item. The use of the REFLECT statement, which addresses issues unique to livestock trials, should improve the quality of reporting and design for trials reporting production, health, and food-safety outcomes. [source] Enabling technologies to improve area-wide integrated pest management programmes for the control of screwwormsMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2009A. S. ROBINSON Abstract The economic devastation caused in the past by the New World screwworm fly Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) to the livestock industry in the U.S.A., Mexico and the rest of Central America was staggering. The eradication of this major livestock pest from North and Central America using the sterile insect technique (SIT) as part of an area-wide integrated pest management (AW-IPM) programme was a phenomenal technical and managerial accomplishment with enormous economic implications. The area is maintained screwworm-free by the weekly release of 40 million sterile flies in the Darien Gap in Panama, which prevents migration from screwworm-infested areas in Columbia. However, the species is still a major pest in many areas of the Caribbean and South America and there is considerable interest in extending the eradication programme to these countries. Understanding New World screwworm fly populations in the Caribbean and South America, which represent a continuous threat to the screwworm-free areas of Central America and the U.S.A., is a prerequisite to any future eradication campaigns. The Old World screwworm fly Chrysomya bezziana Villeneuve (Diptera: Calliphoridae) has a very wide distribution ranging from Southern Africa to Papua New Guinea and, although its economic importance is assumed to be less than that of its New World counterpart, it is a serious pest in extensive livestock production and a constant threat to pest-free areas such as Australia. In the 1980s repeated introductions and an expansion of Old World screwworm populations were reported in the Middle East; in the 1990s it invaded Iraq and since late 2007 it has been reported in Yemen, where a severe outbreak of myiasis occurred in 2008. Small-scale field trials have shown the potential of integrating the SIT in the control of this pest and various international organizations are considering using the release of sterile insects as part of an AW-IPM approach on a much wider scale. Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a screwworm of temperate regions, which, although of limited agricultural importance, has invaded several new locations in the past few years. This special issue reports on the results of a 6-year project funded by the Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency (FAO/IAEA) Programme of Nuclear Techniques in Food and Agriculture entitled ,Enabling Technologies for the Expansion of the SIT for Old and New World Screwworm'. A major goal of the project was to better understand population genetic variation in screwworms as an aid to the identification of isolated populations. The project also addressed issues related to genetic sexing, cuticular hydrocarbons, population dynamics, genetic transformation and chromosome analysis. [source] INVITED REVIEW: Quantitative trait locus mapping in natural populations: progress, caveats and future directionsMOLECULAR ECOLOGY, Issue 2 2005JON SLATE Abstract Over the last 15 years quantitative trait locus (QTL) mapping has become a popular method for understanding the genetic basis of continuous variation in a variety of systems. For example, the technique is now an integral tool in medical genetics, livestock production, plant breeding and population genetics of model organisms. Ten years ago, it was suggested that the method could be used to understand continuous variation in natural populations. In this review I: (i) clarify what is meant by natural population in the QTL context, (ii) discuss whether evolutionary biologists have successfully mapped QTL in natural populations, (iii) highlight some of the questions that have been addressed by QTL mapping in natural populations, (iv) describe how QTL mapping can be conducted in unmanipulated natural populations, (v) highlight some of the limitations of QTL mapping and (vi) try to predict some future directions for QTL mapping in natural populations. [source] Vaccination against the Old World screwworm fly (Chrysomya bezziana)PARASITE IMMUNOLOGY, Issue 11 2000Sukarsih Chrysomya bezziana is an endemic pest of livestock or a threat to livestock production in large areas of Africa, the Middle East, southern and south-east Asia and Australia. Its control is difficult. The feasibility of vaccinating against this pest has now been explored. In-vitro and in-vivo assays have been established. Using these assays, it has been shown that first instar larvae, third instar peritrophic membrane and cardia are all sources of material able to induce immunological reactions in sheep which lead to significant reductions in larval growth. In-vitro assays following vaccination with peritrophic membrane also show larval mortality. Taken together, these effects lead to an 82% reduction in the weight of recovered larvae in vitro and 45% reduction in vivo. Preliminary evidence suggests that the mechanism of protection may be complex. [source] First report of cyromazine resistance in a population of UK house fly (Musca domestica) associated with intensive livestock productionPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2010Howard A Bell Abstract BACKGROUND: House fly control in livestock-rearing facilities is heavily reliant on the use of the larvicide cyromazine. While extensive use of this compound has led to the development of resistance in several countries, no elevated tolerance has so far been reported from the United Kingdom. RESULTS: Tolerance to cyromazine in larvae derived from a field strain collected at an intensive pig unit was significantly elevated over that of insects taken from a susceptible laboratory strain. Resistance factors (RFs) of 2.9 and 2.4 were returned for assays initiated with eggs and neonate larvae respectively. The RF for field strain larvae exposed from neonate increased significantly to 3.9 and 5.6 following rounds of selection at 1.0 and then 1.5 mg kg,1 cyromazine. CONCLUSION: Low-level resistance to cyromazine in UK house flies is reported here for the first time. The geographic extent of this resistance is unknown but, if widespread, may lead to control failures in the future, and indicates that careful stewardship of this compound in the United Kingdom is now required. © Crown copyright 2010. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] Grass cells ingested by ruminants undergo autolysis which differs from senescence: implications for grass breeding targets and livestock productionPLANT CELL & ENVIRONMENT, Issue 10 2002E. M. Beha Abstract It is widely believed that the initial degradation of proteins contained in grazed forage is mediated by rumen micro-organisms, but the authors' recent work suggests that the plant cells themselves contribute to their own demise. In the present study the responses of Lolium perenne leaves to the rumen environment were investigated by using an in vitro system which simulates the main stresses of the rumen but from which rumen micro-organisms were excluded. Degradation of leaf protein and the accumulation of amino acids in tissue and bathing medium occurred over a time-scale that is relevant to rumen function, and in a near 1 : 1 ratio. Significant loss of nuclear material was observed after 6 h incubation and chloroplasts became morphologically more spherical as the incubation progressed. In situ localization suggested that ribulose 1,5 bisphosphate carboxylase/oxygenase was broken down within chloroplasts which from cytology were judged to be intact. We conclude from these data that plant metabolism may play a significant role in breaking down plant proteins within relatively intact organelles in the rumen. The determinations of chlorophyll content and cell viability revealed that the plant processes occurring in the simulated rumen were similar but not identical to those of natural senescence. [source] Risk factors for serious injury in Finnish agricultureAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2009Risto H. Rautiainen PhD Abstract Background Previous studies indicate 20% of injuries represent 80% of injury costs in agriculture. To help prevent the most costly injuries, we aimed to identify characteristics and risk factors associated with serious injuries. Methods We analyzed insurance records of 93,550 self-employed Finnish farmers. We ranked injury causes by claim cost and used multiple logistic regressions to identify risk factors for (any) injury and serious injury (injuries exceeding claim costs of ,2000). Results A total of 5,507 compensated injuries occurred in 2002 (rate 5.9/100 person-years), and 1,167 or 21% of them (rate 1.25/100 person-years) were serious. The causes/sources resulting in highest average claim costs were motor vehicles; stairs, scaffoldings, and ladders; trailers and wagons; floors, walkways, and steps; other structures and obstacles; augers, mills, and grain handling equipment; horses; combines and harvesting equipment; tractor steps; and uneven and slippery terrain. Older age, male gender, higher income level, greater field size, residing on the farm, Finnish language (vs. Swedish), occupational health service (OHS) membership, and animal production were risk factors for injury. The risk factors for serious injury were similar; however, the effects of age, income level, and the raising of horses were more prominent. Language, residence, ownership status, and OHS membership were not risk factors for serious injury. Conclusions Cost-effective prevention efforts should address the following risk factors: older age, male gender, larger income and operation size, livestock production (particularly dairy, swine, and horses), motor vehicle incidents, falls from elevation, and slips, trips and falls. Am. J. Ind. Med. 52:419,428, 2009. © 2009 Wiley-Liss, Inc. [source] Improving the Efficiency of Insemination with Sex-sorted SpermatozoaREPRODUCTION IN DOMESTIC ANIMALS, Issue 2008JM Vazquez Contents The sorting of X- and Y-chromosome-bearing spermatozoa by flow cytometry is nowadays one of the most apt assisted-reproduction technologies in livestock production. Potential economic and biological benefits, as well as those related to easier management of herds, have been reported arising out of the application of this technique, especially in cattle. Yet, the sex-sorting procedure induces damage to spermatozoa, affecting their function and fertilizing ability. Different species present varying degrees of susceptibility to damage from the sorting process and each has its own requirements for sex-sorted insemination procedures. Thus, several new protocols and strategies have been designed for the handling of sorted spermatozoa, with the main objective of optimizing their fertilizing ability and the consequent application of flow-cytometric sex-sorting technology. This article reviews current advances in this technology, pointing out the components to be improved before this technology may be widely applied in different domestic species. [source] Climate change and the characterization, breeding and conservation of animal genetic resourcesANIMAL GENETICS, Issue 2010Irene Hoffmann Summary Livestock production both contributes to and is affected by climate change. In addition to the physiological effects of higher temperatures on individual animals, the consequences of climate change are likely to include increased risk that geographically restricted rare breed populations will be badly affected by disturbances. Indirect effects may be felt via ecosystem changes that alter the distribution of animal diseases or affect the supply of feed. Breeding goals may have to be adjusted to account for higher temperatures, lower quality diets and greater disease challenge. Species and breeds that are well adapted to such conditions may become more widely used. Climate change mitigation strategies, in combination with ever increasing demand for food, may also have an impact on breed and species utilization, driving a shift towards monogastrics and breeds that are efficient converters of feed into meat, milk and eggs. This may lead to the neglect of the adaptation potential of local breeds in developing countries. Given the potential for significant future changes in production conditions and in the objectives of livestock production, it is essential that the value provided by animal genetic diversity is secured. This requires better characterization of breeds, production environments and associated knowledge; the compilation of more complete breed inventories; improved mechanisms to monitor and respond to threats to genetic diversity; more effective in situ and ex situ conservation measures; genetic improvement programmes targeting adaptive traits in high-output and performance traits in locally adapted breeds; increased support for developing countries in their management of animal genetic resources; and wider access to genetic resources and associated knowledge. [source] Effect of dietary probiotic Biogen® supplementation as a growth promoter on growth performance and feed utilization of Nile tilapia Oreochromis niloticus (L.)AQUACULTURE RESEARCH, Issue 14 2006E R EL-Haroun Abstract Probiotic microbial feed supplements are gaining wide acceptance in livestock production, and may be applicable to aquaculture production systems. The present study was conducted to examine probiotic treatment in the fingerling diet of Nile tilapia Oreochromis niloticus (L.). A total of 240 of Nile tilapia fingerlings (weight ranged from 22.96 to 26.40 g) were divided into five experimental groups. The experiment was conducted for 120 days. Experimental diets were identical in all, except for the variation in probiotic levels. A probiotic (Biogen®) was used at 0% (diet 1), 0.5% (diet 2), 1.5% (diet 3), 2.0% (diet 4) and 2.5% (diet 5) inclusion rates in the experimental diets. The growth performance and nutrient utilization of Nile tilapia including weight gain, specific growth rate, protein efficiency ratio, protein productive value and energy retention were significantly (P,0.01) higher in the treatment receiving probiotic (Biogen®) than the control diet. No differences were observed for moisture, ash and protein content (P,0.01) among the experimental diets. The lowest gross energy and lipid contents were recorded for fish fed the diet containing 0.5% Biogen® (P,0.01). The production performance and subsequent cost,benefit analyses clearly indicated that the diets containing probiotic biogen recorded the highest net return and the lowest total cost compared with the control diet. [source] Strain differences in feed efficiency measured as residual feed intake in individually reared rainbow trout, Oncorhynchus mykiss (Walbaum)AQUACULTURE RESEARCH, Issue 7 2005Jeffrey T Silverstein Abstract The efficient use of feed for growth and meat production is important for all animal production industries including aquaculture. Residual feed intake (RFI) is an alternative measure of feed efficiency that has been widely used in livestock production. Residual feed intake was calculated as the difference between intake observed and intake predicted on the basis of a bioenergetics model; a low RFI indicates greater efficiency. Residual feed intake offers some advantages as a selection criterion for improving production efficiency over traditional feed efficiency statistics because it is not a ratio and it typically has a larger coefficient of variation. The RFI of individually reared rainbow trout progeny from six different genetic cross-types was examined for genetic variation. Proximate analysis and nitrogen retention were also evaluated to determine if differences in RFI correlate to differences in body composition and nutrient retention and varied by cross-type. Differences between cross-types indicated a genetic component for RFI, with the most efficient fish of approximately 160 g consuming 0.99 g less and inefficient fish consuming 0.05 g more feed per day than expected. Lower RFI was associated with higher growth rates (r=,0.38, P<0.05) and greater nitrogen retention (r=,0.82 P<0.001). [source] Future developments in global livestock and grains markets: the impacts of livestock productivity convergence in Asia-PacificAUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 3 2000Allan N. Rae Increasing livestock product consumption in many Asian countries has been accompanied by growth in some countries' imports of feedgrains for their domestic livestock sectors. This contributes to debate over future levels of grain imports. Yet projections often pay little attention to developments in livestock production. The impacts of technological catch-up in livestock production on trade in livestock and grains products among countries in the Asia-Pacific region are assessed. Tests are conducted of the hypothesis that productivity levels in the Asia-Pacific region are converging. Projections of livestock productivity are made and incorporated in a modified GTAP model. The consequences for regional and global trade in livestock and grains products are explored. [source] Effects of Market and Regulatory Changes on Livestock Manure Management in Southern AlbertaCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 2 2006Elwin G. Smith A spatial model of intensive livestock production for a region in southern Alberta was used to evaluate the impact of economic factors and regulation on regional returns and optimal manure management. Under current conditions, profit maximizing application of manure met nitrogen requirements but phosphorus application was about three times the crop requirements. Higher commercial nitrogen prices did not significantly alter the optimal manure application, but reduced regional returns. With a phosphorus limit regulation, it was less costly to compost about half of the beef cattle manure to remove it from the region than to truck manure long distances to meet the regulation. A $0.91/t reduction in the costs of composting, or a subsidy to reduce costs, was required to meet the phosphorus regulation. The net costs of the subsidy were slightly less than that ofphosphorus regulation. Future research needs to explore the economic market and limitations of composting for manure management before any composting policy is initiated. Nous avons utilisé un modèle spatial de la production animale intensive dans une région du sud de l'Alberta pour évaluer l'impact de la réglementation et de facteurs économiques sur les rendements économiques régionaux et la gestion optimale du fumier. Dans les conditions actuelles, l'épandage de fumier effectué en vue de maximiser les profits a respecté les exigences en azote, tandis que la quantité de phosphore était trois fois supérieure aux besoins des cultures. Le prix élevé de l'azote commercial n'a pas modifié de manière significative l'épandage optimal de fumier, mais a diminué les rendements économiques dans la région. En raison de la réglementation sur le taux d'application limite du phosphore, il a été moins coûteux de composter environ la moitié du fumier de bovins pour l'éliminer de la région que de le transporter par camion sur de longues distances. Pour respecter la réglementation sur le phosphore, il faudrait diminuer le coût du compostage de 0,91 $/tonne ou offrir une subvention équivalente pour diminuer les coûts. Les coûts nets de la subvention étaient légèrement inférieurs à ceux de la réglementation sur le phosphore. Des recherches ultérieures devront être effectuées pour explorer le marchééconomique et les limites du compostage dans le cadre de la gestion du fumier avant d'élaborer toute politique sur le compostage. [source] China's New Rural Income Support Policy: Impacts on Grain Production and Rural Income InequalityCHINA AND WORLD ECONOMY, Issue 6 2006Nico Heerink D58; Q12; Q18 Abstract This paper analyses the impact of agricultural tax abolition and direct income payments to grain farmers on grain production and rural inequality in China. To separate the impact of the income support measures from recent price trends for grains and inputs, and to account for differences in household responses, we use a village-level general equilibrium model that we calibrate for two villages with different degrees of market access in Jiangxi province. The results show that the income support policy does not reach its goal of promoting grain production. The increased incomes allow farm households to buy more inputs for livestock production and involve other activities that are more profitable than grain farming. Selling of rice outside the villages declines more than rice production, because households in the villages consume more rice when incomes rise. We further find that the income support measures tend to reduce income within a village, but that tax abolition tends to widen income inequality between villages. (Edited by Zhinan Zhang) [source] | ||||||||||||||||||||||