牛羊体尺的聚类与主成分分析

分别对牛羊体尺进行了聚类与主成分分析，所得结果对牛羊品种选育、鉴定、评价有一定指导意义，并为畜体测量学的建立提供一种新的思路和依据。     

顺手牵羊新编

春秋时期，秦将孟明视率领大军准备偷袭郑国，而郑国对此毫无觉察。郑国有个贩卖牛羊的商人，名叫弦高，善于随机应变。他与两个同伴在半途偶然遇到浩浩荡荡的秦军，知道情况不妙，便急中生智，一边派人回国通风报信，一边把自己的几头羊献给秦将孟明视。弦高恭敬地对孟明视说：“今日郑国的国君听说将军前来，特奉上一点儿薄礼以示心意。”孟明视听罢大吃一惊，以为郑国早有防备，想偷袭已经不可能了，便移师攻打滑国。弦高的本来目的是贩卖牛羊，却顺势以羊为礼物，替郑国解了大围。这件事情对弦高来说，是顺手牵羊。此“羊”虽然不小，但终归是顺势而成的事。     

藏獒多吉（上）

这是一片矗立在青藏高原的山麓原野,青青的牧草,蔚蓝的天空,巍峨的山脉。 这里有四处漂移的帐房,成群的牛羊,随时埋伏在草丛或岩石后伺机偷袭的熊豹豺狼,还有像野兽一样身体壮硕的大狗——藏獒。     

基于能源消费二重性的经济增长模型

能源作为国民经济生产最基本的物质基础,既是国民经济生产中不可或缺的生产要素,又是人们日常生活中必不可少的消费对象.对能源消费的这种二重性进行了分析,建立了考虑能源消费二重性的经济增长模型.讨论了生产、消费用能源的最优配置条件及资本折旧率、效用贴现率对经济均衡点资本存量的影响.     

生产函数构成的树形图分析方法

作为生产函数几何表示的尝试，本文通过对生产函数要素构成的分析，归纳出一种用树形图表示生产函数的方法，这种方法直观形象，能清晰地表示各要素之间的结构关系和指标关系．     

顺手牵羊新编

春秋时期,秦将孟明视率领大军准备偷袭郑国,而郑国对此毫无觉察。郑国有个贩卖牛羊的商人,名叫弦高,善于随机应变。他与两个同伴在半途偶然遇到浩浩荡荡的秦军,知道情况不妙,便急中生智,一边派人回国通风报信,一边把自己的几头羊献给秦将孟明视。弦高恭敬地对孟明视说:"今日郑国的国君听说将军前来,特奉上一点儿薄礼以示心意。"孟明视听罢     

黑龙江省畜牧业发展水平的因子分析模型构建与综合评价研究

通过构建因子分析模型成功实现了黑龙江省畜牧业发展水平的综合评价.本文首先剖析了因子分析模型的基本原理与评价实施过程;其次,针对全国31个省份畜牧业发展水平的8个关键指标建立因子分析模型,最终求得涵盖猪牛羊生产能力、畜牧业贡献能力在内的黑龙江省畜牧业整体竞争能力位列全国第12位,有效证明了应用因子分析模型解决畜牧业发展水平评价问题具有较强能力,值得进一步推广使用.     

C-D生产函数在林产品投入产出中的应用研究

本文运用C-D生产函数，并结合闽西北毛竹的密度效应模型和产量模型，对其进行弹性分析和边际产量分析。提出用C-D生产函数建立毛竹密度效应模型的优越性，为达到合理、高效的营林工作提供科学依据。     

瓷石和高岭土样品分类的研究

本文用Ｑ型聚类法对瓷石１３个样品，高岭土１９个样品进行分类研究，其分类结果对陶瓷工业生产有一定的指导意义。     

基于改进混合遗传算法安排生产调度

研究了某工厂生产调度问题,建立了数学模型.针对这一实际问题,通过引入小生境技术、最优保存策略、近优淘汰策略、自适应调整交叉概率和变异概率,设计了用于求解多个最优顺序的混合遗传算法,用所设计的混合遗传算法对该模型进行了计算,获得了许多最优顺序,这就使得生产调度安排灵活机动,便于智能调度,同时生产量比原来大幅度提高.这表明使用混合遗传算法安排生产调度是非常有效的.     

Mathemetical modelling for the control and prevention of animal production diseases

A computerized information-retrieval system for slaughterhouse-condemnationand meteorological data was established in Northern Irelandin 1986. The system has been used to study the epidemiologyof economically important diseases of cattle, sheep, and pigswhich occur during the production period. The system containsinformation on condemnations recorded in all abattoirs in NorthernIreland since 1969 and a concurrent database of all major prevailingweather variables. The software available on the system enablescomplex time-series analyses of the integrated database on aroutine interactive basis. The computerized system has been used to highlight, to the agriculturalindustry, the continued importance of the control and preventionof a number of animal production diseases. In this paper, wedescribe the formulation of a new mathematical model which accuratelyforecasts the annual prevalence of fasciolosis in cattle. Theforecasts form the basis of specific veterinary advice on thestrategic use of effective control measures.     

A Linear Programming Model for an Integrated Crop and Intensive Beef Production Enterprise

In an integrated crop and intensive beef production enterprise, some of the feedstuffs used for cattle feeding are grown by the enterprise. In evaluating the performance of operations of this type, the interactions between the crop and beef production parts of the enterprise must be taken into account. A linear programming (L.P.) model of this type of enterprise is developed, with the coefficients of the animal feeding activities being derived from a dynamic programming (D.P.) model. This D.P. model is used to determine the least-cost method of feeding animals to produce a specified liveweight gain using rations formulated by L.P. from a given set of feedstuffs. This approach allows the interactions between crop and livestock production to be taken into account without the need to make assumptions about the source of feedstuffs or the rate of liveweight gain.     

GENERAL EQUILIBRIUM ECOSYSTEM MODELING WITH ALTERNATIVE PREFERENCE SPECIFICATIONS

This paper reconciles two sets of literature with regard to the interactive ecological and economic impacts of invasive grass species and cattle stocking. We model cattle as optimal foragers, satiation foragers, and proportional foragers in order to understand the impact that each assumption imposes on predicted economic and ecological outcomes. Through this model sensitivity (as opposed to parameter sensitivity) analysis, we are able to identify three main drivers of plant invasions: exogenous forces such as climate change or nitrogen deposition, poor land management decisions, and a misalignment of incentives between cattle and ranchers even when ranchers behave optimally.     

Mathematical analysis of a model for the transmission dynamics of bovine tuberculosis

A deterministic model for studying the transmission dynamics of bovine tuberculosis in a single cattle herd is presented and qualitatively analyzed. A notable feature of the model is that it allows for the importation of asymptomatically infected cattle (into the herd) because re‐stocking from outside sources. Rigorous analysis of the model shows that the model has a globally‐asymptotically stable disease‐free equilibrium whenever a certain epidemiological threshold, known as the reproduction number, is less than unity. In the absence of importation of asymptomatically infected cattle, the model has a unique endemic equilibrium whenever the reproduction number exceeds unity (this equilibrium is globally asymptotically stable for a special case). It is further shown that, for the case where asymptomatically infected cattle are imported into the herd, the model has a unique endemic equilibrium. This equilibrium is also shown to be globally asymptotically stable for a special case. Copyright © 2011 John Wiley & Sons, Ltd.     

Split-delivery routeing heuristics in livestock feed distribution

In this paper, we describe a feed distribution problem encountered on a cattle ranch in Arizona. The problem is cast as a collection of split-delivery capacitated rural postman problem with time windows on arcs. We discuss the generic problems and several heuristics. The heuristics we discuss were tested and compared favourably with the working practices on the cattle ranch.     

Price discovery in the Texas cash cattle market

Time series methods and directed acyclic graphs are used to uncover the centre of price discovery in 10 weight/gender classes of feeder and fed cattle from cash markets in Texas, U.S.A. Heavy feeder heifers, animals sitting on a margin of feeding for meat or breeding for new stocks, are weakly exogenous in an error correction representation of these prices. Further, contemporaneous price innovations from this class of animals cause price innovations in feeder steers and lighter weight feeder heifers. Innovation accounting shows the prominent role that heavy heifers play in cattle price discovery. Copyright © 2004 John Wiley & Sons, Ltd.     

Profit optimization for cattle growing in a randomly fluctuating environment

A class of stochastic differential equation models was applied to describe the evolution of the weight of Mertolengo cattle. We have determined the optimal mean profit obtained by selling an animal at the cattle market, using two approaches. One consists in determining the optimal selling age (independently of the weight) and the other consists in selling the animal when a fixed optimal weight is achieved for the first time (independently of the age). The profit probability distribution can be computed for such optimal age/weight. For typical market values, we observed that the second approach achieves a higher optimal mean profit compared with the first one, and, in most cases, even provides a lower standard deviation.     

A Parametric Programming Method for Beef Cattle Ration Formulation

Ration formulation is an important aspect of the operation of many beef cattle enterprises. The method for beef cattle ration formulation depends on the system used to specify the nutrient requirements of the animals. With the system which is recommended by the Ministry of Agriculture, Fisheries and Food in the U.K., difficulties arise in ration formulation because the energy requirements of the animal depend on the energy concentration of the ration. A method for formulating rations to satisfy the recommended nutrient standards is developed. The approach involves using parametric linear programming to obtain a piecewise representation of the cost of the ration as a function of the energy concentration of the ration, and then using differential calculus to determine the least cost ration.     

关于牲畜繁殖销售的动态规划模型的进一步探讨

本分别用前向和后向最优化原理考察了牲畜繁殖销售问题，根据收益函数的凹凸性，给出了一些相应的计算公式。