紫貂泌乳期饲粮适宜能量浓度与蛋白质水平的研究

为探讨紫貂泌乳期饲粮适宜的能量浓度与蛋白质水平,本研究选用90只产仔紫貂进行3(GE:4900,5300和5700Kcal/kg)×3(CP:40,45和50％)二因子交叉饲养试验和代谢试验。试验结果表明,以仔兽体重和消化、代谢参数为主要指标,紫貂泌乳期饲粮适宜的GE浓度和CP水平分别应为4900～5300Kcal/kg和40％～45％,且互作效应最好的组合力GE4900Kcal/kg×CP45％,其次是GE5300Kcal/kg×CPd5％、GE4900Kcal/kg×CP40％和GE5300Kcal/kg×CP40％。随着饲根GE浓度的提高,泌乳母貂断奶时体重相应提高,而日存留氮和氮存留率均逐渐降低。能量代谢率和氮存留率随着饲粮CP水平的提高而逐渐降低。     

ANALYSES OF THE DIFFERENCE BETWEEN IRRIGATED AND NONIRRIGATED AREA FOR LUMINOUS ENERGY UTILIZATION RATIO AND PRODUCTIVE POTENTIALITIES IN NINGXIA

<正> Situated in arid and semi-arid lands, the Ningxia Hui Autonomous Region is locatedat the middle reaches of the Yellow River. An adequate system of gravity irrigation was es-tablished in the north of Ningxia. Adding to abundant sunshine, strong solar radiation andmoderate heat, the agriculture is very developed. The south mountainous area of Ningxia, including both Yanchi and Tongxin counties,is short of rain, The vast lands cannot be irrigated. Nonirrigated agriculture and serious     

A review of the effect of energy intake on pregnancy rate and litter size-discussed in relation to group-housed non-lactating sows

The number of group-housed non-lactating sows is increasing rapidly in Europe as a consequence of changed legislation initiated by elevated public concern of animal welfare. Lower litter size and pregnancy rate in group compared to individually housed non-lactating sows have been observed in several on-farm experiments. The overall aim of this paper is to consider whether the variation in energy intake in a group of non-lactating sows can influence variation in litter size and pregnancy rate. A review of existing literature with main emphasis on publications after 1980 was carried out to clarify whether pregnancy rate and litter size may be influenced by energy intake. The studies reviewed indicate that low energy intake compared to high energy intake before mating may impair litter size in gilts and in sows that experienced severe weight loss during lactation. Furthermore, moderate energy intake compared to low energy intake in the first 3 days after mating may reduce litter size in the gilt but not in the sows. Both pregnancy rate and litter size might be influenced by very low energy intake in the first 4 weeks of pregnancy. Based upon studies indicating that low ranking sows may consume considerably less than high ranking sows (e.g., 50-80%) in group-housed systems, it is suggested that the variation in feed intake in a group of restricted fed pregnant female pigs may be large enough to influence pregnancy rate and litter size.     

草地生态资产及功能价值的能值评估--以锡林郭勒羊草草地为例

运用能值理论和方法，对锡林郭勒羊草样地生态系统运行的主要驱动力、内在过程、生态资产贮量及其服务功能价值进行了评估。结果表明，1hm^2草地生态系统平均每年对区域经济贡献的宏观经济实际价值约为7285．94元，主要生态资产的宏观经济理论价值约为10580．06元，而1hm^2羊草样地生态系统的替代价值约为39724元。由此可以估算出对羊草草地在开发过程中其环境服务功能及生态资本的损失，另外，也可以根据生物量的减少及GPP的变动情况对生态系统的服务功能及生态资本变动情况进行评估。同时可以根据草地生态系统功能退化的程度进一步估算出区域生态系统损失的情况．可为毕杰粟缔补偿棚制的律寺据供科举依据．     

下切式节能旋耕刀研究

指出了降低旋耕刀切土功耗的技术途径,建立了节能旋耕刀解析设计理论及计算机辅助设计计算方法。试验结果表明,节能旋耕刀的切土功耗显著低于现有旋耕刀,二者耕作质量相同。     

泵站配电设备的节能途径

在进行泵站节能技术改造时，实施节能的主要途径有：经济可靠的接线方式、高效运行的配电线路以及较高的功率因数等。对已建成的功率因数偏低的泵站采用电力电容补偿，可减少电源和线路的电流负荷。     

离心泵变速调节节能浅析

泵站的经济运行就是要求以最少的能耗获得最大的经济效益。本文从离心泵变速调节原理入手,探讨了以节能为目标的离心泵变速调节的计算方法和效果。     

中小型电力排灌站节能改造分析

泵站节能技术改造工作在我国一些省份已取得了相当大的经济效益，但作为商品粮基地的黑龙江省，排灌泵站还存在着一系列问题亟等解决。文章分析了黑龙江省排灌站长期以来存在的问题及其形成原因，并对问题较为典型的两个泵站进行了深入研究，针对泵站具体情况提出相应改造方法，并进行了经济效益评估，为中小电力排灌站节能技术改造提供了可借鉴的经验和范例。     

喷灌分区的能量分析

文章分析了喷灌系统的能量组成及利用情况，在此基础上，提出了分区能量图解法，并得出一级建站与多级建站分区节省供水能量相同的结论．