Monitoring and Controlling Mastitis on Ontario Dairy Farms

The frequency of use and the marginal costs and marginal value products of mastitis control practices on somatic cell count (SCC) and milk yield are investigated. A survey of current management practices is combined with Dairy Herd Improvement production information to determine the relationships between milk yield, SCC, management practices, and production and producer characteristics under field conditions. The relationships are modeled and compared at the cow and herd level. A moment-generating approach is used in the herd model to determine which, if any, practices are risk reducing. The SCC for an individual cow is a better indicator of milk production lost due to mastitis than is a bulk tank SCC. Most recommended mastitis control practices are estimated to be economically beneficial, but some common practices are found not to be economical, and questions are raised about dry cow treatment. On a examiné la fréquence à laquelle on recourt aux pratiques de lutte contre la mammite, de même que les couts et les avantages marginaux de ces dernières en ce qui concerne la numération des cellues somatiques et le rendement laitier. On a combiné une enquête sur les pratiques zootechniques actuelles aux renseignements sur la production extraits du Programme d'amélioration des troupeaux laitiers en vue de déterminer les relations qui existent entre le rendement laitier, la numération des cellules somatiques, la conduite du troupeau ainsi que les caractéristiques associées à la production et aux producteurs, sur le terrain. On a ensuite modélisé ces relations et on les a compareées entre les animaux et les troupeaux. Pour le modèle touchant les troupeaux, on s'est servi d'une approche générant des moments, pour déterminer si une pratique quelconque diminuait les risques. La numération des cellules somatiques chez la vache est un meilleur indicateur du volume de lait perdu à la suite de la mammite que la numération des cellules somatiques dans la citerne. La plupart des méthodes de lutte contre la mammite recommendées offrent un avantage économique, mais certaines pratiques courantes ont l'effet contraire et on s'interroge sur l'utilité de traiter les vaches taries.     

美国以自然资源保护为宗旨的土地休耕经验

美国土地休耕制度包括一系列水土保持计划和以土壤侵蚀度为主要指标的水土保持评价标准,它通过一系列耕地保护计划来推行。回顾美国农业耕作土地采取休耕政策及其实施情况,讨论了值得我国学习和借鉴的土地休耕计划的政策的成本费用等问题。     

The Marine Environment: Fencing the Last Frontier

Fisheries resources contribute a valuable source of protein to the world's food supply. While there is much promise for continued production gains from aquaculture and terrestrial sources, the marine fisheries sector faces a number of critical current policy junctures. Since extension of jurisdiction to 200 miles in 1976, there have been dramatic changes in the opportunity for coastal nations to rationally manage formerly open access marine resources. While more spatially encompassing management has brought physical yield close to full biological potential, much of the potential economic yield from fisheries is still squandered. An important issue is whether the future potential of marine resources will be guided by an expansion of private property rights or by an expansion of bureaucratic regulatory structures. New monitoring, information, and enforcement technology is making it increasingly possible to zone the ocean and implement measures that mimic terrestrial property systems. At the same time, there is opposition to privatizing marine resources by groups who view them as public resources. The outcome of the tussle between the forces supporting and opposing property rights creation will largely determine the extent and kinds of values that will be generated from marine resources around the world in the next decade.     

THE MEASUREMENT OF MANAGERIAL EFFICIENCY IN AGRICULTURE*

This paper is an outline only of a Ph.D. thesis submitted to the University of Nottingham. The paper proposes a socio-economic model of farm production with special emphasis placed on the role of management: formulates an econometric model, to represent the socio-economic model, in which the degree of managerial efficiency appears as a variable, and suggests means of interpretation of the econometric model to aid farm planning at the individual farm level.     

尼日利亚西部农业推广监督员监督和管理能力及其决定

在发展中国家，由于工作环境较差、工作动力不足和职业能力的下降，使推广人员的工作效率大大削弱。为了对农业推广进行干预，就要对人力资源的能力进行定期分析，从而为适当的培训和能力建设提供合理的依据。本研究，采用多阶段随机抽样方法对70个尼日利亚西南部的农业推广监督员进行调研，对尼日利亚西南部农业推广监督员的管理和监督职能、特点以及工作条件进行了分析。信息通过问卷形式收集，该问卷基于Haynes（1996）设计和验证的工具变量。数据分析用百分比、平均等级、标准差、排名法和变异数（ANOVA）等方法。研究表明，农业推广监督员需要定期地在职训练以提高他们的专业能力，同时应当改善服务条件。