肥育犊牛肝病的诊断和预防     

B.M.Дaнилeвcкий  宋明德 《动物医学进展》1988,(5)

本文对专业农场肥育公牛犊的肝病提出了诊断指标。在此基础上用硒和维生素E进行预防并与对照组相比,肝功指标正常,每头牛日增重高94～114克。  相似文献   

降低家禽饲料的营养水平效益可观     

Du－c.  WA 杨禄良 《国外畜牧科技》1993,(1):27-28

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ENABLING CROP DIVERSIFICATION TO SUPPORT TRANSITIONS TOWARD MORE SUSTAINABLE EUROPEAN AGRIFOOD SYSTEMS     

Antoine MESS&#  AN  Lo&#  c VIGUIER  Lise PARESYS  Jean-No&#  l AUBERTOT  Stefano CANALI  Pietro IANNETTA  Eric JUSTES  Alison KARLEY  Beatrix KEILLOR  Laura KEMPER  Fr&#  d&#  ric MUEL  Barbara PANCINO  Didier STILMANT  Christine WATSON  Helga WILLER  Ra&#  l ZORNOZA 《农业科学与工程前沿(英文版)》2021,8(3):474

• Crop diversification is a dynamic pathway towards sustainable agrifood systems.• Technological and institutional barriers restrict uptake of crop diversification.• More coordination and cooperation among agrifood system stakeholders is required.• The European Crop Diversification Cluster calls for multiactor networks.European cropping systems are often characterized by short rotations or even monocropping, leading to environmental issues such as soil degradation, water eutrophication, and air pollution including greenhouse gas emissions, that contribute to climate change and biodiversity loss. The use of diversification practices (i.e., intercropping, multiple cropping including cover cropping and rotation extension), may help enhance agrobiodiversity and deliver ecosystem services while developing new value chains. Despite its benefits, crop diversification is hindered by various technical, organizational, and institutional barriers along value chains (input industries, farms, trading and processing industries, retailers, and consumers) and within sociotechnical systems (policy, research, education, regulation and advisory). Six EU-funded research projects have joined forces to boost crop diversification by creating the European Crop Diversification Cluster (CDC). This Cluster aggregates research, innovation, commercial and citizen-focused partnerships to identify and remove barriers across the agrifood system and thus enables the uptake of diversification measures by all European value-chain stakeholders. The CDC will produce a typology of barriers, develop tools to accompany actors in their transition, harmonize the use of multicriteria assessment indicators, prepare policy recommendations and pave the way for a long-term network on crop diversification.  相似文献   

日粮钙源颗粒大小对不同年龄产蛋鸡生产性能和蛋壳质量的影响     

M.Sk 《中国家禽》2011,33(10)

在蛋鸡生产中,人们主要关注其产蛋后期的蛋壳质量比较差,易碎.影响蛋鸡产蛋后期蛋壳质量的主要因素是蛋鸡的年龄和日粮中的钙.NRC(1994)估测蛋鸡钙的营养需要为每天每100g摄入的日粮中含有32.5 g/kg.然而,许多专家通过试验证实,当66～78周龄蛋鸡日粮中钙的含量由24～25 g/kg提高到36～40 g/kg时可以将产蛋率从79%提高到86%,蛋壳重量可以由5.64 g提高到6.12g,壳重/壳表面积由712提高到77.4mg/cm2.日粮中钙的含量提高至48～50 g/kg并不能进一步提高产蛋率,但是可以改善蛋壳重量和蛋壳厚度.58～73周龄伊莎蛋鸡日粮中添加40 g/kg钙就可以保证其产蛋性能和蛋壳质量.  相似文献   

新生仔猪产CNF大肠杆菌的实验感染     

Wray  c 顾有方 《国外兽医学(畜禽传染病)》1994,14(4):17-19

为了检测和比较大肠杆菌（Ｅ．ｃｏｌｉ）产生的细胞毒素坏死因子（ＣＮＦ），用１０＾１０Ｅ．ＣｏｌｉＯ３２菌株口服接种２窝仔猪。在２４小时内，接种Ｅ．ｃｏｌｉＯ８８的６头仔猪死亡２头，３头发生腹泻，其他仔猪于接种后１、５、６和８天屠宰，细菌培养表明感染Ｅ．ｃｏｌｉ者，早期整个大肠发生菌血症；呈现的早期肠炎病变，发展为小肠结肠炎；菌血症扩展到肺部；组织学病变为脑、心、肝和肾出现毒血症，呈充血、水肿和渗出  相似文献   

母猪慢性子宫内膜炎的诊断与治疗     

б.c.Cлйридонов  谢敏康 《动物医学进展》1988,(5)

母猪慢性子宫内膜炎没有明显的临床症状,在工业化养猪业综合体,有15-20％母猪患病。在交配或人工授精前,临床观察发现518头母猪有慢性子宫内膜炎。母猪乏情期,没有子宫分泌物。此时,阴道检查也未发现有子宫疾病的任何症状。机体全身状态、体温、脉搏和呼吸都处在生理学范围之内。随着兴奋期开始,即看到生殖器排泄大量的卡他性或卡他脓性渗出物(特别是早晨在栏圈内躺卧地点)。大多数母猪性周期未破坏;但是,尽管  相似文献   

Infectivity and pathogenicity of Cryptosporidium andersoni to a novel host, southern multimammate mouse (Mastomys coucha)     

Kvác M  Ondrácková Z  Kvetonová D  Sak B  Vítovec J 《Veterinary parasitology》2007,143(3-4):229-233

The infectivity and pathogenicity of Cryptosporidium andersoni (bovine isolate) for neonatal and adult southern multimammate mice (Mastomys coucha) was studied using transmission experiments. C. andersoni isolate used in this study was not infective for BALB/c mice, but experimental infection proved susceptibility of neonatal and adult M. coucha to the infection. The prepatent period was 20-24 days, the patent period varied between 46 and 59 days. No signs of clinical illness or macroscopic findings were detected in infected animals. Cryptosporidium developmental stages were detected only in the glandular part of the stomach of M. coucha in histological sections stained with Wolbach's modification of Giemsa and using immunofluorecence. Histopathological changes were characterized by dilatation and epithelial metaplasia of infected gastric glands without inflammatory response in the lamina propria. Neonatal M. coucha were more susceptible to C. andersoni infection than adults. M. coucha seems to be a useful laboratory model for study of C. andersoni infection.  相似文献   

Detecting a fault line under a single phase to ground of distribution network based on analysis of multi frequency bands     

LI Xin  LI Jing liab  ZHANG Cong lic  LUO Jianab 《保鲜与加工》2008,(10):1143-1148

Addressing the problem of choosing a fault line under single phase to ground of distribution network, we presented a new criterion based on analysis of the development of fault line selection and a method using wavelet packets. The feature frequency band, or the combined feature frequency bands of each line, in which the transient capacity current was concentrated was chosen for maximum energy. Based on the principle that the transient capacity current's energy of the fault line was larger than the that of normal lines, fault line selection can be carried out adaptively by contrasting the energy of the transient capacity currents of all lines in each chosen frequency band. The simulation results and spot testing data shows the proposed method can detect the fault line in distribution networks precisely and reliably.  相似文献   

基于遗传算法的皮尔逊Ⅲ型曲线参     

宋茂斌  冯宝平  张展羽c 《中国农村水利水电》2008,(6):52-54

皮尔逊Ⅲ型频率曲线参数估计时,常用方法有矩法、权函数法和适线法等,这些方法各有缺陷。根据遗传算法全局寻优的原理与特点,采用遗传算法计算皮尔逊Ⅲ型频率曲线的三个参数,并和其他方法进行了对比验证。结果表明,遗传算法得到的频率曲线与实测资料误差小,拟合精度高,是一种较好的计算方法,值得推广应用。  相似文献   

应用模糊数学方法评价全射流喷头     

杨炎财  李红刘孟 陈超 王超c 《中国农村水利水电》2008,(7):29-31

旋转式喷头的水力性能主要是由射程、流量、工作压力、喷灌强度、喷灌均匀度、水滴打击强度等六项指标综合决定,应用模糊综合评判的数学模型并结合试验数据评价国内外摇臂式喷头及全射流喷头的水力性能,结果表明隙控式全射流喷头比摇臂式喷头有更优越的水力性能。应用模糊数学方法时,权重分配会对评价结果产生影响,应根据实际需要选择最优的权重分配。  相似文献