甘南野生豆科牧草资源及其评价

通过对甘南境内野生豆科牧草资源的调查，摸清了该地区野生豆科牧草的资源状况，对其饲用价值、栽培驯化、育种价值、营养成分、经济性状等进行了综合评价。在高寒牧区豆科牧草品种奇缺的情况下，开发当地有饲用价值的野生豆科牧草，是提高该地区草地生产力水平、改善饲草营养状况的必由之路。     

牧草适应性的定量化研究

为了实现对牧草适应性的定量化研究,以草原综合顺序分类法、牧草生长的气候适宜度、牧草种或品种的生物学特性理论为依据,确定了牧草适应性影响因子,并采用模糊逻辑和层次分析法建立了其隶属函数;在地理信息系统(GIS)平台的支持下,建立了数据库并形成了牧草适应性的GIS产品.通过这些研究,得出了牧草适应性的定量化定义.     

AHP在牧草价值综合评定中的应用

为了寻找一种客观、准确地评价牧草的方法,试验采用与营养成分、适口性、生物学特性、生产特性、生态价值等密切相关的22个指标构建综合评价模型,应用层次分析法把复杂的问题进行分解,方便、简易地对牧草价值进行了综合评定。结果表明:此方法可以把牧草的饲用价值评定进行多层次的拆解,使原本复杂、繁琐的评价变得简单化。     

玉米草SAUMZ1不同生育期饲用价值的分析

牧草饲用价值受许多因素的影响，运用AHP模型对新品种玉米草SAUMZ1不同生育期饲用价值进行综合评价，为其合理利用奠定基础。结果表明，饲用价值是化学成分、适口性和消化率等综合作用的结果；粗蛋白因素在饲用价值评价中所占的比重较大，一般情况下，粗蛋白含量越高，饲用价值也越好；综合排序为拔节期〉抽穗初期〉抽穗后期〉开花期。     

鲁北滨海地区引种豆科牧草的灰色关联度分析

试验在鲁北滨海地区对经一般观察后初步入选的１４种豆科牧草进行了观察，并采用灰色关联度分析法以干草产量、鲜草产量、繁殖系数、折干率、叶量率、生长速度为主要指标进行综合评价。结果表明：综合性状最好的豆科牧草是草木樨属牧草，其中白花草木樨尤为突出；其次为沙打旺和美国苜蓿，也是适于鲁北滨海地区种植的豆科牧草。     

典型草原打草场主要牧草生产特性、 营养成分及饲用价值评价

以典型草原5种主要牧草羊草(Leymus chinensis)、大针茅(Stipa grandis)、达乌里胡子枝(Lespedeza davurica)、扁穗冰草(Agropyron cristatum)和中华隐子草(Cleistogenes chinensis)为研究对象,通过饲料常规营养成分的检测分析和牧草品质评定预测公式对其生产特性、营养成分及饲用价值进行综合分析比较。结果表明:大针茅的产量最高,为235.06 kg/hm2,牧草营养成分高低排序为:扁穗冰草大针茅中华隐子草羊草达乌里胡枝子,饲用价值高低排序为:扁穗冰草大针茅羊草中华隐子草达乌里胡枝子。结合牧草的实际生产产量,综合评价5种牧草的利用价值及质量品质为:扁穗冰草大针茅中华隐子草羊草达乌里胡枝子。本研究可以为该地区典型草原主要牧草在家畜营养中的应用提供合理的参考依据。     

非生物胁迫下牧草抗逆性研究进展

非生物胁迫(低温、高温、干旱、水涝、盐害等)是影响牧草生长和发育的重要因素，因而探究牧草抗逆性响应特征、指标、评价方法和提升途径，对于提升和稳定牧草生产有重大意义。本文通过文献资料调研和计量分析方法，综述了牧草对温度、水分和盐分等非生物胁迫作用的响应，概述了牧草的形态结构、生理生化和生产性能抗逆性指标，总结了6类牧草综合评价方法的原理和优缺点，综述了4种牧草抗逆性提升途径，并对今后在非生物胁迫下牧草抗逆性方向上需开展的3个方面研究工作进行展望，以期为选取牧草抗逆性指标和评价方法，提升牧草质量和产量提供参考依据。     

新围沿海滩涂人工草地生产技术与效率评价的研究

本文系统地综述了在新围沿海滩涂盐渍化土地上，因地制宜，分类治理滨海盐土的方法，研究了南方沿海滩涂人工草地的建植技术和培育措施；并从牧草种类的选择和组合及其生产量、营养物质保证率、成本，价值等指标，选择最适宜的数量标准，综合评价了牧草的生产效率，为沿海滩涂草地建设提供了科学依据。     

串叶松香草的引种研究

通过对串叶松香草的形态特征、生物学特性、产量及营养价值等项目的观察和测定，对其利用价值进行了综合评价，指出串叶松香草是一种有前途的优质多年生牧草。     

鄂温克草原常见禾本科牧草营养价值的综合评价与对应分析

以内蒙古鄂温克草原的8种禾本科牧草为对象,通过主成分分析法确定牧草营养价值评价指标之间的相互关系,在此基础上运用基于变异系数赋权的灰色关联综合评价法对8种禾本科牧草的营养价值进行了综合评价,采用双标图方法对牧草种类与评价指标的相互关系进行了对应分析。结果显示:8种禾本科牧草的综合营养价值由高到低依次为羊草、冰草、羽茅、■草、糙隐子草、草地早熟禾、贝加尔针茅、大针茅。     

A theoretical analysis of foraging efficiency of grazing animals

A mathematical model of the change in quantity of forage during grazing is constructed, assuming (1) that forage requirement by grazing animals is constant, and (2) that intake is equal to requirement when forage is in free supply but (3) that below a certain supply level intake becomes restricted and is proportional to supply. Grazing efficiency is then defined in terms of utilization of the forage present at the start of the period of restricted intake. The need, or otherwise, for a high grazing efficiency can be determined, given the acceptable level of utilization of forage. A particular part of the period of restricted intake is identified; the herd has to remain until well past the end of this part period, to achieve a high grazing efficiency. Because the animals are under stress during this time, it must be made as short as possible. Some ways of doing so are discussed. Subdivision of the grazing area into smaller camps can be an effective way of increasing grazing efficiency, but this method is not the only one which is practicable and it could even decrease efficiency. A formula for calculating the required number of camps is given. It can be used to give the stocking density required.     

我国草种质资源的保护现状、存在问题及建议

草种质资源是生物多样性的重要组成部分,是国家重要的战略资源。我国草种质资源保护工作在保护体系构建、收集保存、鉴定评价、种质创新、共享利用等方面取得了显著成效,但还存在缺乏原生境保护措施、特有珍稀资源消失风险加剧、评价创新严重滞后等问题。今后应加强重点保护草种质资源的原生境保护、加大重点属种收集保护力度、强化资源的系统评价和深度发掘,充分发挥草种质资源对草种业的支撑作用。     

川北地区紫花苜蓿品种筛选及栽培技术研究

用灰色系统理论对11个苜蓿（Medicago sativa）品种在川北丘陵低山区的生产性能(鲜草产量、干草产量、茎叶比、株高、分枝数、主根长、再生速度等指标)进行了分析,建立了综合评价模型,评价了各品种的生产性能。结果表明,各项指标在综合评价模型中的权重顺序为株高>分枝数>主根长>鲜草产量>茎叶比=再生速度>干草产量;在川北地区综合生产性能表现较好的紫花苜蓿品种是猎人河、霍普兰德和WL323等,爱菲尼特、特瑞和农宝等品种生产性能较差,苜蓿王和胜利两个品种虽然鲜草产量较高,但其再生速度慢,且苜蓿王茎叶比低,胜利干物质含量低,因而综合评价较差。     

Simulation of cow-calf production systems in a range environment: I. Model development

A mathematical computer model of beef cattle production systems was developed at Montana State University. The objective of this report was to describe the rationale and procedures used to simulate animal and system performance. The model was designed to simulate the dynamic relationships among cattle genotype, physiological state, forage quality, and management in range environments. Forage intake, energy and protein metabolism, growth, reproduction, lactation, and changes in chemical body composition are simulated for individual animals over complete life cycles. Expenses driven by animal performance, management decisions, and land resources are tabulated. Several biological and economic measures of system performance can be computed, including ratios of inputs (e.g., DM, CP, ME, dollars) to outputs (e.g., weight, lean), break even prices, and annual gross margin per cow or ranch. Primary uses of the model include the evaluation of system responses to changes in breeding strategies and management in range production/marketing systems.     

紫花苜蓿对干旱胁迫适应性的研究进展

苜蓿是抗旱且需水较多的豆科牧草,水分供应不足会使其受到干旱胁迫的危害,从而导致农艺性状,如草产量、种子产量、叶片形态和根系特征等,均发生改变.同时,苜蓿体内也发生一系列生理生化反应来消除或降低干旱胁迫的伤害作用,即阻止、减少或抵消干旱胁迫诱导的生理生化过程.本研究综述和讨论了苜蓿的特征特性及其对干旱胁迫的响应、抗旱性评价和缓解干旱胁迫的途径等研究进展.     

Evaluation of a feed intake model for the grazing beef steer

Responses of a feed intake model for grazing beef cattle to changes in model parameters, forage composition, and supplementation programs with energy and protein were evaluated. Without supplements, the model systematically underpredicted intake of low-quality (low digestibility) forages and subsequent overprediction was observed for high-quality diets. In general, for a reference diet of Italian ryegrass, the model was relatively insensitive to microbial growth parameters, highly sensitive to the microbial carbohydrate composition constant, and moderately sensitive to the microbial N composition constant. Intake prediction was sensitive to changes in the microbial use rate constant for fiber but insensitive to those for protein and starch. Model predictions were highly sensitive to the amount of nondegradable fiber in each of the forages tested. Supplementation effects on forage intake were quantified by supplementing all forage diets with chemical components equivalent to that provided by 1 kg of corn grain or 1 kg of cottonseed meal. Supplementation of the forage diet with the concentrate source resulted in substitution ratios of forage to supplement intake consistent with in vivo results. As forage quality increased, substitution of concentrate for the forage increased. However, the model failed to predict the increased forage intake typically observed with protein supplementation, suggesting that it is insufficient for intake prediction in protein-limiting situations. Nevertheless, the model correctly predicted effects of energy supplementation and forage composition on forage intake, suggesting that different controls must regulate intake responses to supplemental protein.     

A computer model to predict empty body weight in cattle from diet and animal characteristics.

A computer model was developed to predict empty BW in cattle as a function of diet (forage NDF, physical form of forage [hay vs silage and pasture], proportion of dietary concentrates) and animal (full BW) characteristics. The model was empty BW = full BW * (1 - GFILL), where GFILL is gut fill expressed as a fraction of full BW. An equation obtained from published data (GFILL = .05354 + .329 * NDF) was used to provide a base prediction of GFILL from the fraction of NDF in the forage. Predicted GFILL was then corrected for full BW, physical form of forage, and fraction of concentrates using multiplicative factors obtained from published data. The model was evaluated with data from 11 published experiments. Several breeds of cattle, a wide range of forage types, and diets with 0 to 93% concentrates were represented in these data. Observed values for empty BW were compared to model-predicted values and to values predicted by systems published by the Agricultural Research Council (ARC) and National Research Council (NRC). Sums of squared deviations of predicted values from observed (n = 64) were 3,074, 37,327, and 25,920 for the model, ARC, and NRC systems, respectively. After fitting predicted empty BW values to observed values, proportion of concentrates and forage NDF accounted for a significant (P less than .01) amount of the residual variation with the ARC and NRC systems, but not for the model. This finding suggests that the model will predict empty BW more accurately than the ARC and NRC systems with diets similar to those used in the evaluation.     

用灰色关联系数法对苜蓿品种生产性能综合评价

在灰色系统下,对13个苜蓿Medicago sativa品种在兰州的生产性能用株高、再生速度、鲜草产量、分枝数、叶量等指标进行分析,建立品种评价模型,综合评价各品种的生产性能.结果表明,在兰州地区生产性能表现较好的苜蓿品种有L33、新疆大叶、L173、PL55、Algongun等, 而河西、陇东、陇中等品种生产性能较低.根据各项指标的权重比较分枝数所占的权重>株高>叶量>鲜草产量>再生速度.     

Energy intake and requirement of dairy cows during the whole year

It is argued that in view of the many new methods in dairy farming an economic model of the dairy farm should be available to improve advisory work. Some quantitative data concerning the dairy cow needed for such a model are given. They deal with a net energy feeding value of grass, hay, silage, artificially dried grass and concentrates estimated with a feed evaluation system based on results obtained with lactating cows. Also data on the requirements for net energy and for long forage dry matter are given, again obtained with such cows. Finally information is given on voluntary intake of forage dry matter at pasture, from fresh grass fed indoors, from various preserved forages including forage pellets, as influenced by milk yield and condition of the cow and by kind of forage and level of concentrates fed. Special attention has been paid to the precision of the information. These data are used to predict both the maximal and minimal amounts of long forage which can be fed in the stall period without loss of production, and the additional quantities of concentrates needed. For the grazing cow the problem of the adjustment of voluntary intake of grass to milk yield and amount of concentrates fed is studied. It is concluded that the information is sufficient to develop an economic model of a dairy farm. For its development grassland research should supply data on pasture yield in terms of digestible organic matter when the forage is fed to sheep at the maintenance level, and the economists should add data on costs of food and labour.