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文章对粉碎及分级原理做了基本介绍,结合分级原理对饲料行业常用的粉碎粒度的表征方法做了进一步的探讨,并建议在有筛式粉碎机的学术研究中增加d80作为行业通称的粉碎粒度,增加S80=χ=d80/d20作为有筛式粉碎机粉碎制品均匀度的指标;在饲料行业超微粉体的研究中,建议采用显微镜替代标准筛作为粒度检测的工具。并以特征粒径d80或切割粒径d50作为超微粉体粒度指标,以S80=χ=d80/d20作为饲料行业用空气分级机的分级精度指标,同时作为超微粉体的粒度均匀性指标,采用牛顿分级效率ηN作为空气分级机分级效率的评判依据。 相似文献
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糖甜菜不仅是糖料作物，而且其收获和制糖后的副产品都有很高的饲料价值，每公顷生产的饲料单位高于饲用甜菜等块根类饲料作物，其茎叶营养价值与苜蓿接近；糖甜菜抗逆性强，对温度适应范围广，耐旱、耐寒、抗盐碱，用于开发饲料具有重要的经济意义，在农业种植结构调整中，糖甜菜作为饲料作物纳入三元结构中有显著优势。 相似文献
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持续感染是指病原体在宿主体内持续存在而不被清除的状态,其潜伏期长达数月至数年甚至终生,但不引起症状,病原体不一定持续增殖。不同病原体所致持续感染的定义不同,如口蹄疫病毒(FMDV)引起的持续感染被定义为动物感染28d后仍然携带活的病毒。持续感染是造成免疫失败、肿瘤形成或药物敏感性下降的重要原因。存在持续感染的宿主是重要的传染源,还是病原体发生变异的来源,但因无症状常被忽视。充分了解持续感染的形成机理及持续感染状态中宿主与病原体之间的相互作用,有助于寻找诊断、治疗和预防感染性疾病的最佳方法。论文从病原体和宿主因素两个方面阐述了持续感染的形成机理。 相似文献
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Feed efficiency represents the cumulative efficiency with which the pig utilizes dietary nutrients for maintenance, lean gain and lipid accretion. It is closely linked with energy metabolism, as the oxidation of carbon-containing components in the feed drive all metabolic processes. While much is known about nutrient utilization and tissue metabolism, blending these subjects into a discussion on feed efficiency has proven to be difficult. For example, while increasing dietary energy concentration will almost certainly increase feed efficiency, the correlation between dietary energy concentration and feed efficiency is surprisingly low. This is likely due to the plethora of non-dietary factors that impact feed efficiency, such as the environment and health as well as individual variation in maintenance requirements, body composition and body weight.Nonetheless, a deeper understanding of feed efficiency is critical at many levels. To individual farms, it impacts profitability. To the pork industry, it represents its competitive position against other protein sources. To food economists, it means less demand on global feed resources. There are environmental and other societal implications as well.Interestingly, feed efficiency is not always reported simply as a ratio of body weight gain to feed consumed. This review will explain why this arithmetic calculation, as simple as it initially seems, and as universally applied as it is in science and commerce, can often be misleading due to errors inherent in recording of both weight gain and feed intake.This review discusses the importance of feed efficiency, the manner in which it can be measured and reported, its basis in biology and approaches to its improvement. It concludes with a summary of findings and recommendations for future efforts. 相似文献
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不同利用方式下(刈割和放牧),比较了羊草(Leymus chinensis)草地土壤微生物多样性(真菌、细菌和放线菌)及群落结构的数量变化。结果表明:土壤微生物的数量在不同利用方式下表现为:刈割草地>放牧草地,在不同植物群落中表现为:羊草群落>杂类草群落>碱茅(Puccinellia distans)群落。无论在刈割还是放牧区,真菌的分布为:羊草群落>杂类草群落>碱茅群落;细菌的分布为:杂类草群落>羊草群落>碱茅群落;放线菌为:羊草群落>杂类草群落>碱茅群落。土壤微生物随土层垂直递减分布,在土层0~15 cm土壤微生物分布最多。3类微生物中,细菌数量最大, 放线菌次之, 真菌最小。相关性分析表明,只在刈割方式下羊草群落(sp1)和碱茅群落(sp2)土壤的微生物数量与地上生物量显著相关(P<0.05),其余相关性均不显著。 相似文献
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对青藏高原东南部天然草地有毒有害植物进行了野外调查、资料收集及室内研究的基础上,建立了青藏高原东南部天然草地有毒有害植物数据库。本数据库信息系统采用Visual Basic 6.0中文版设计,整个信息系统分为系统管理模块和数据查询模块两部分。系统管理模块下设数据管理模块,可对数据进行录入、修改和删除操作;数据查询模块提供一个可视化、人性化界面,设置查询窗体、显示数据窗体和详细信息窗体,并具有浏览功能。在今后对青藏高原有毒有害植物的研究中,该数据库可方便、有效地管理有毒有害植物的知识和资料并实现数据的搜集、查询、保存和处理。本文首次对青藏高原东南部天然草地有毒有害植物数据库的研制成果进行了报道。 相似文献
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本文经过钻孔资料分析和周边矿井的调查研究、判断对比,认为虽然平禹一矿立井掘进时表土层深厚,含水层、含砂层既多又厚,涌水量大,但不会形成流砂。只要采取针对性措施如采用外壁套挂、短段掘砌、快挖快进混合作业,采用堵、降、导、排、桩等联合治水,加强支护等完全可以采用普通法施工。本文详细阐述了平禹一矿立井施工技术,为以后类似条件的井筒施工提供了先进的施工经验,有着较好的社会经济效益和推广价值。 相似文献
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大豆磷脂理化性质及其在猪饲料中的应用 《畜牧与饲料科学》2016,37(5):16-16
大豆磷脂是一种具有特殊理化性质和营养功能的植物性油脂,在饲料中的应用非常广泛。在猪饲料中添加大豆磷脂可提高断奶仔猪存活率和饲料转化率,改善母猪的繁殖性能。主要对大豆磷脂的理化性质、生理功能及其在养猪生产中的应用作一介绍,以期为养殖人员提供参考。 相似文献
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为阐明大肠杆菌耐药菌株药物敏感性变化与acrA和marA的mRNA水平之间的关系。用定量RT—PCR方法比较了多重耐药菌株、单药耐药菌株以及质控株ATCC25922的actA和marA的mRNA水平。结果。actA mRNA水平。多重耐药菌株SEMR是单药耐药菌株SEICI、SEICH和质控株ATCC25922的16倍；／natA mRNA水平。SEMR是SEICH的4倍、SEICI和ATCC25922的8倍；SEICI和SEICH的actA mRNA、marA mRNA水平与ATCC25922的无明显差异；同一菌株actA mRNA和marA mRNA水平的变化保持了较为稳定的一致性。结论：大肠杆菌多重耐药菌株的actA mRNA和marA mRNA水平与其耐药水平存在相关性。 相似文献
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Caroline Ritter Annabelle Beaver Marina A. G. von Keyserlingk 《Reproduction in domestic animals》2019,54(Z3):29-37
Using reproduction parameters as indicators for cattle welfare has limitations and, at best, these parameters should only be viewed as indirect indicators of welfare. On a farm level, measures such as fertility rates emphasize biological performance of the herd but fail to consider the welfare of individual animals. Even on an individual level, the relationship between reproductive effectiveness and animal welfare is complex. Good reproductive performance does not automatically signify good welfare, as domestication and targeted breeding programmes have led to prioritization of high productive and reproductive performance in most modern farm animal species. In this review, we synthesize literature regarding cattle husbandry, reproduction, welfare and their multidimensional relationships. We argue that practices such as artificial insemination or the use of sexed semen may provide potential welfare advantages as these practices reduce the risk of disease transmission and injury or enable selection of specific beneficial traits. Furthermore, they may offer a solution to current practices jeopardizing welfare, such as the management of surplus bull calves in the dairy industry. Conversely, the animals’ ability to perform natural behaviours such as oestrous expression, an aspect arguably contributing to welfare, is often limited on commercial farms; this limitation is particularly evident in housing systems such as tie stalls where movement is restricted. Moreover, common management practices such as oestrus manipulation may lead to negative attitudes in citizens who often regard naturalness as important element of animal welfare. 相似文献
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J. L. Davis 《Equine Veterinary Education》2017,29(2):104-113
Right dorsal colitis in horses is a disease characterised by mucosal ulceration and oedema that is localised to the right dorsal colon. It is considered one of the more severe adverse effects associated with the use of nonsteroidal anti‐inflammatory drugs (NSAIDs), particularly phenylbutazone. Diagnosis is typically made based on a history of NSAID administration, the presence of hypoproteinaemia and hypoalbuminaemia, as well as ultrasound evidence of thickening and oedema of the right dorsal colon wall. Definitive diagnosis is made at surgery or necropsy. Treatment involves discontinuation of NSAID therapy, dietary management, and mucosal protectants such as misoprostol and sucralfate. Prognosis is dependent upon early recognition and appropriate treatment. Horses on prolonged courses of NSAIDs should have frequent monitoring of serum total protein and albumin concentrations, as this is one of the earliest and most consistent clinicopathological findings. 相似文献
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建立中兽药制剂护肝颗粒的成型工艺,考察单一辅料以及不同配比的蔗糖和糊精分别制粒后,对颗粒成型性、溶化性、抗湿性的影响。结果表明,混合辅料蔗糖-糊精（2∶1）,所得颗粒成型性好,溶化性好、抗湿性强。本成型工艺可为护肝颗粒最终处方的确定以及投入生产时环境的控制提供一定的依据。 相似文献
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Karin Müller Susanne Eder Ulrike Jakop Jürgen Schiller Peter Müller Mohammad Bashawat 《Reproduction in domestic animals》2020,55(Z2):55-60
Cryobanking of gametes in combination with artificial insemination is an essential option to support conservation programmes for endangered and threatened species. About two-thirds of the felid species are classified as ‘near threatened’, ‘vulnerable’ or ‘endangered’ ( www.cites.org ), and mostly, epididymal sperm are collected from euthanized or castrated male felids and cryopreserved. However, epididymal compared with ejaculated and cryopreserved compared with fresh sperm have a limited potential to fertilize if vaginal non-surgical insemination is applied in feline species. Missing or highly diluted seminal fluid in epididymal and cryopreserved sperm, as well as a potential interference of extender ingredients with the natural interactive properties of sperm in the female genital tract is discussed as potential drawback which hampers a proper sperm transit and fertilization besides the limited longevity of cryopreserved feline sperm. Individual components in seminal fluid as well as cryoextenders may adversely alter sperm properties and have a different impact on fertility and preservation success. The identification and investigation of beneficial as well as detrimental components is a precondition to deduce options for improving the process of cryopreservation in felids, particularly, if only epididymal sperm are available. 相似文献
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Heile C Heydorn AO Schein E 《Berliner und Münchener tier?rztliche Wochenschrift》2006,119(7-8):330-334
This work deals with occurrence, distribution as well as biology and vectorial capacity of the ornate dog tick (Dermacentor (D.) reticulatus). Until 30 years ago this tick has only been described in a few natural foci in southern Germany. Its distribution has however expanded in the course of the last years. With the exception of northern Germany it is now covering large areas of Germany. This is particularly the case in the Upper Rhine Valley, Saarland and the Mark Brandenburg. However, it is endemic in many other areas of Germany as well. The transformation of agricultural land into fallow land, an increase in host reservoirs and climatic changes are discussed as main contributors to this change. Little is known about the role of this species as a vector for virus, rickettsia, bacteria and protozoa as well as its medical and veterinary importance. D. reticulatus is a vector for Babesia canis canis. It is reported here about a case of autochthonous babesiosis in a dog from Berlin/Brandenburg. 相似文献
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Prenni JE Avery AC Olver CS 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2007,36(1):13-24
Proteomics is a rapidly expanding field of scientific study that combines techniques in protein solubilization and separation, mass spectrometry, and genome and protein database searching. The proteome is most commonly defined as the entire complement of proteins expressed in a given cell type or tissue under a given condition. A proteomics experiment may be as simple as identifying a single protein or as complex as identifying thousands of proteins in a cell lysate. In this review, we describe the general principles of proteomics and its analytic methods and present an example of an experiment to characterize the murine reticulocyte membrane proteome. A brief summary of proteomics applications and their clinical potential and relevance to clinical pathology is also presented. 相似文献