Residues of 9 antimicrobial agents approved in México for veterinary use in dairy cattle (sulfathiazole, sulfamerazine, sulfamethazine, sulfachloropyridazine, sulfamonomethoxine, sulfamethoxazole, nitrofurazone, furaltadone, and furazolidone) and non-approved chloramphenicol residues were studied every two weeks in four commercial brands of Mexican pasteurized milk (A, B, C and D) during one year (n=4×24=96). Drug residues were analyzed by high pressure liquid chromatography HPLC with UV detection. Percentage of positive samples to sulfonamide residues were 47.2% (Milk A), 58.3% (Milk B), 44.7% (Milk C) and 50% (Milk D). Sulfonamide residues ranged between 1.9 and 180µg/kg. sulfathiazole and sulfamerazine were the most common residues found. Only three samples (Milk B) exceeded maximum residue levels established for sulfonamides. Nitrofuran residues were not detected in any milk sample. Illegal Chloramphenicol residues were detected in one milk sample (Milk A) in levels of 27.2µg/kg. | Os resíduos de 9 agentes antimicrobianos aprovados no México para seu uso veterinário no gado leiteiro (sulfatiazol, sulfamerazina, sulfametazina, sulfacloropiridazina, sulfamonometoxina, sulfametoxazol, nitrofurazona, furaltadona e furazolidona), assim como de cloranfenicol, cujo uso está proibido na produção pecuária, foram determinados no leite integral pasteurizado e comercializado na Cidade do México. Quatro indústrias de leite (A, B, C e D) foram estudadas quinzenalmente durante um ano (n=4×24=96). Os resíduos foram analisados por cromatografia de líquidos de alta pressão (HPLC) com detector UV. A porcentagem de amostras positivas a resíduos de sulfonamidas foi de 47,2% (leite A); 58,3% (leite B); 44,7% (leite C) e 50% (leite D). Os resíduos de sulfonamidas estiveram no intervalo de 1,9 a 180µg/kg. Resíduos de sulfatiazol e sulfamerazina foram os mais encontrados. Somente três amostras (leite B) excederam os níveis de resíduo máximo estabelecidos para sulfonamidas. Não se detectaram resíduos de nitrofuranos em nenhuma das amostras de leite analisadas. Resíduos de cloranfenicol foram detectados numa amostra de leite (leite A) com um nível de 27,2µg/g. | Los residuos de 9 agentes antimicrobianos aprobados en México para su uso veterinario en el ganado lechero (sulfatiazol, sulfamerazina, sulfametazina, sulfacloropiridazina, sulfamonometoxina, sulfametoxazol, nitrofurazona, furaltadona y furazolidona), así como de cloranfenicol, cuyo uso está prohibido en la producción pecuaria, fueron determinados en leche entera pasteurizada y comercializada en la Ciudad de México. Cuatro industrias de leche (A, B, C y D) fueron estudiadas quincenalmente durante un año (n=4×24=96). Los residuos fueron analizados por cromatografía de líquidos de alta presión (HPLC) con detector UV. El porcentaje de muestras positivas a residuos de sulfonamidas, fueron 47,2% (leche A); 58,3% (leche B); 44,7% (leche C) y 50% (leche D). Los residuos de sulfonamidas estuvieron en el intervalo de 1,9 a 180µg/kg. Residuos de sulfatiazol y sulfamerazina fueron los más encontrados. Sólo tres muestras (leche B) excedieron los niveles de residuo máximo establecidos para sulfonamidas. No se detectaron residuos de nitrofuranos en ninguna de las muestras de leche analizadas. Residuos de cloranfenicol fueron detectados en una muestra de leche (leche A) con un nivel de 27,2µg/g.

As reaction to distinct negative effect of modern agricultural technology and techniques on preservation and protection of environment, lately research of alternative methods of efficient agricultural production in conditions of necessary ecological limits is intensified. The term alternative, biological, ecological or organic agriculture are often determined as systems and methods of plant and livestock production which are in collision with system of ordinary agriculture. Alternative agriculture represents production system which avoids or considerably excludes the application of synthetic mineral fertilizers, pesticides growth regulators and food additives. For control and management of product quality ISO 9000 standards were adopted, and for management of quality of environment is determined by standards ISO 14000. Main purpose of legislatory regulations is protection of health of the population and biodiversity. Standards and regulations on protection of environment valid in EU will be applied on the territory of member states. They will directly or indirectly be transferred through various market mechanisms to wide European area. Adjustment of Serbian economy includes harmonization with the EU policy on protection of the environment which will enhance the competitiveness of Serbian economy on European and world market.

The U.S. agricultural sector is experiencing significant structural change. Farm size is rising and activities are broadening, including more off-farm employment, implying economic incentives for larger and more diversified farms, and complementarities among agricultural netputs. We quantify such patterns for farms in the corn belt, by measuring scale economies, and output and input contributions and jointness. We estimate the multi-output and -input production technology by stochastic frontier techniques applied to output and input distance functions. We find that both scope and scale economies have important economic performance implications, and that an input-oriented framework including off-farm income best characterizes agricultural production.

Based on analysis of business system in agriculture, in this thesis the general - theoretical, logical and mathematical model for optimal year planning of plant production was defined. Optimization was solved at the level of fields. Different variants of model was defined depends of objective functions: maximal grose margin, maximal efficiency, and compromise optimazation. Aiming at its evaluation and verification the model was tested for the case of one agricultural enterprise.

Many Nicaraguan peasants remain members in agricultural production cooperatives despite the change in the policy environment that now supports parcellation of cooperative lands into individual holdings. Institutional factors, such as uncertainty of land ownership rights and difficulties with resolution of cooperative debt, are found to play a dominant role in keeping Nicaraguan peasants in cooperatives.

This document presents innovations in agricultural risk management for natural disaster risk, with the focus on defining practical roles for governments of developing countries and the World Bank in developing risk management strategies. The paper includes the following content: introduction; risk and risk management in agriculture, including informal and formal mechanisms; approaches to agricultural risk in developed countries; innovation in managing production risk - index insurance; new approaches to agricultural risk management in developing countries; from theory to practice: pilot projects for agricultural risk transfer in developing countries; and potential roles for governments and the World Bank.

BACKGROUND: The importance of molybdenum for plant growth is disproportionate with respect to the absolute amounts required by most plants. Apart from Cu, Mo is the least abundant essential micronutrient found in most plant tissues and is often set as the base from which all other nutrients are compared and measured. Molybdenum is utilized by selected enzymes to carry out redox reactions. Enzymes that require molybdenum for activity include nitrate reductase, xanthine dehydrogenase, aldehyde oxidase and sulfite oxidase. SCOPE: Loss of Mo-dependent enzyme activity (directly or indirectly through low internal molybdenum levels) impacts upon plant development, in particular, those processes involving nitrogen metabolism and the synthesis of the phytohormones abscisic acid and indole-3 butyric acid. Currently, there is little information on how plants access molybdate from the soil solution and redistribute it within the plant. In this review, the role of molybdenum in plants is discussed, focusing on its current constraints in some agricultural situations and where increased molybdenum nutrition may aid in agricultural plant development and yields. CONCLUSIONS: Molybdenum deficiencies are considered rare in most agricultural cropping areas; however, the phenotype is often misdiagnosed and attributed to other downstream effects associated with its role in various enzymatic redox reactions. Molybdenum fertilization through foliar sprays can effectively supplement internal molybdenum deficiencies and rescue the activity of molybdoenzymes. The current understanding on how plants access molybdate from the soil solution or later redistribute it once in the plant is still unclear; however, plants have similar physiological molybdenum transport phenotypes to those found in prokaryotic systems. Thus, careful analysis of existing prokaryotic molybdate transport mechanisms, as well as a re-examination of know anion transport mechanisms present in plants, will help to resolve how this important trace element is accumulated.

Background: The importance of molybdenum for plant growth is disproportionate with respect to the absolute amounts required by most plants. Apart from Cu, Mo is the least abundant essential micronutrient found in most plant tissues and is often set as the base from which all other nutrients are compared and measured. Molybdenum is utilized by selected enzymes to carry out redox reactions. Enzymes that require molybdenum for activity include nitrate reductase, xanthine dehydrogenase, aldehyde oxidase and sulfite oxidase. Scope: Loss of Mo-dependent enzyme activity (directly or indirectly through low internal molybdenum levels) impacts upon plant development, in particular, those processes involving nitrogen metabolism and the synthesis of the phytohormones abscisic acid and indole-3 butyric acid. Currently, there is little information on how plants access molybdate from the soil solution and redistribute it within the plant. In this review, the role of molybdenum in plants is discussed, focusing on its current constraints in some agricultural situations and where increased molybdenum nutrition may aid in agricultural plant development and yields. Conclusions: Molybdenum deficiencies are considered rare in most agricultural cropping areas; however, the phenotype is often misdiagnosed and attributed to other downstream effects associated with its role in various enzymatic redox reactions. Molybdenum fertilization through foliar sprays can effectively supplement internal molybdenum deficiencies and rescue the activity of molybdoenzymes. The current understanding on how plants access molybdate from the soil solution or later redistribute it once in the plant is still unclear; however, plants have similar physiological molybdenum transport phenotypes to those found in prokaryotic systems. Thus, careful analysis of existing prokaryotic molybdate transport mechanisms, as well as a re-examination of know anion transport mechanisms present in plants, will help to resolve how this important trace element is accumulated. | Brent N. Kaiser, Kate L. Gridley, Joanne Ngaire Brady, Thomas Phillips, and Stephen D. Tyerman

The purpose of this article is to identify the fundamental factors that are key determinants in promoting effective operation of Agricultural Production Cooperatives (APCs). A theoretical framework "determinants of APCs' performance" was used to analyze the links between the webs of factors. A survey method was used to collect data from two southern provinces in Iran. Data were collected from 52 managers and 260 member farmers in 52 APCs using a stratified random sampling method. It is concluded that the theoretical model can to a great extent predict the performance of APCs. Cooperative structure and government support factors are the most important factors explaining the performance of APCs. Also, policy strategies need to focus on conditioning variables that affect the performance of APCs.