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猪肺炎支原体净化检测程序研究进展 总被引：1，自引：1，他引：0
猪支原体肺炎（猪气喘病）是由猪肺炎支原体引起的一种严重危害全球养猪业生产的传染病之一。很多国家,特别是西欧各国和北美,均通过彻底净化病原的方式来控制该病的爆发。实行净化程序必须对净化后的猪群进行各项检测以确定净化成功与否。然而,每个猪场采用的检测方案都不一样,也没有形成一个统一的阴性群标准。本研究就国外猪肺炎支原体净化后阴性群的检测方法和不同检测方案做一综述,给国内猪场实施气喘病净化后检测方案的制定提供依据。 相似文献
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猪肺炎支原体气溶胶富集检测技术的初步研究 总被引：1，自引：1，他引：0
为了建立一个简单易行的猪肺炎支原体气溶胶富集和检测技术,结合液体冲击式采样器和过滤式采样器的原理,自行设计一个气溶胶双重富集装置,并在密闭环境下采集人工制备的猪肺炎支原体气溶胶,荧光定量PCR检测以确定该装置的采集效率。再通过收集不同猪群中的气溶胶进行检测以确定该装置临床应用的可行性。首先,收集人工感染Mhp阴性仔猪后不同时间猪舍内的气溶胶;其次,收集1个猪支原体肺炎发病猪场和1个阳性未发病猪场的产房、保育舍和育肥舍共11个猪舍的气溶胶,荧光定量PCR或套式PCR检测所收集的气溶胶。结果显示：实验室模拟采样的采集效率达到(37.04±6.43)%,人工感染猪肺炎支原体后7天即在饲养房间的气溶胶中检到猪肺炎支原体;2个猪场共11个不同猪舍气溶胶中猪肺炎支原体检测结果均为阳性,检出率100%。成功建立了一个简单易行的猪场猪肺炎支原体气溶胶富集及检测技术。 相似文献
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<正>猪支原体肺炎,又称猪地方流行性肺炎,俗称猪气喘病。该病是由猪肺炎支原体引起的猪的一种慢性、接触性传染病。不同品种、日龄、性别的猪都有易感性,一年四季均可发生。患猪和带菌猪是该病的传染源,传播途径主要为呼吸道。该病潜伏期长、病程长,病原体在猪体内存在时间长,患猪在耐过或治愈后半年,甚至更长时间,仍可带菌、排菌。因此,猪场发病后如果净化不彻底,又会造成新进猪只感染,再次发生猪气喘病。 相似文献
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<正> 气候的变化对养猪生产来说是一个不容忽视的重要影响因素。夏季的高温会给养猪生产带来很多不利影响,如群体繁殖性能下降、母猪发生无乳综合征、猪群的采食量下降和生长速度减缓等。在猪场经营中通过加强饲养管理,改善猪群生存环境,最大程度地降低由于高温热应激产生的危害,能更好地发挥猪的生产性能,提高养殖效益。一、改善猪场设施,做好物理降温夏季应当通过物理降温措施来改善环境,减少热应激的影响。1.猪场建筑。屋顶采用易隔热的草料或绝缘材料,如再涂上反光漆,更能减少热量的吸收。最简便的办法 相似文献
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Toll样受体(TLRs)作为重要的模式识别受体,在动物的天然免疫中发挥重要作用,是机体抵抗感染的第一道屏障;TLRs基因变异会改变机体对病原的抗性或易感性,本试验旨在探讨TLR2、TLR4基因突变与支原体肺炎感染的关系。试验以国外引进猪品种(长白、大白、皮特兰)、中国地方猪品种(梅山、二花脸、姜曲海、金华)以及江苏省培育猪品种(苏钟猪)为材料,通过PCR-SSCP技术检测实验猪群TLR2、TLR4基因SNPs分布,结合动物攻毒实验及文献报道,对其中部分SNP不同基因型猪的肺部巨噬细胞做LPS感染实验,借助RT-PCR跟踪不同时间点猪TLR2、TLR4基因以及促炎性因子TNF-α、IL-1β的表达变化,揭示猪Toll样受体基因的变异与支原体肺炎感染的关系。结果表明,本实验猪群TLR4基因存在4个SNP位点:T611A、G960A、G962A、C1027A,其中G960A为同义突变,其余为有义突变;位点C1027A在中、外猪品种间呈现明显的碱基分布差异。LPS诱导下的猪肺部巨噬细胞TLR2、TLR4基因及促炎性因子TNF-α、IL-1β均表现不同程度的表达上调;其中,位点C1027A的CC型猪TLR2、TLR4基因表达水平及增速均显著高于AC型猪(P<0.01),TNF-α、IL-1β的表达水平则显著低于AC型猪(P<0.01),提示C等位基因极可能是猪抗支原体肺炎感染的优势基因。 相似文献
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针对当前猪市持续疲软、北方地区即将进入寒冷冬季的情况,合理调整猪群结构并做好入冬前的准备,是北方中小型猪场必须认真抓好的工作。一、合理调整种猪群结构种猪质量好坏决定着猪群生产水平的高低,种猪群中生产性能低下、繁殖泌乳力差、屡配不孕母猪的存在,大大增加了养猪成本,降低了猪场经济效益。猪市疲软的情况下,应抓住时机淘汰劣质种猪,引进优良种猪,提高种猪质量水平。另外,受 相似文献
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This paper assesses and compares risk in conventional and organic arable farming in The Netherlands with respect to family farm income and underlying price and production variables. To investigate the risk factors the farm accountancy data network was used containing unbalanced panel data from 196 conventional and 29 organic representative Dutch arable farms (for the period 2002 up to and including 2011). Variables with regard to price and production risk were identified using a family farm income analysis scheme. Price risk variables are input and output prices, while yield volatility of different crops is the main production risk variable. To assess risk, an error components implicit detrending method was applied and the resulting detrended standard deviations were compared between conventional and organic farms. Results indicate that the risk at the level of family farm income is higher in organic farming. The underlying variables show higher risk for organic farms in crop yields, crop prices and variable input costs per crop. 相似文献
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The intensification of agriculture in Europe has contributed significantly to the decline of mixed crop-livestock farms in favour of specialised farms. Specialisation, when accompanied by intensive farming practices, leaves farms poorly equipped to sustainably manage by-products of production, capture beneficial ecological interactions, and adapt in a volatile economic climate. An often proposed solution to overcome these environmental and economic constraints is to recouple crop and livestock production via cooperation between specialised farms. If well-managed, synergies between crop and livestock production beyond farm level have the potential to improve feed and fertiliser autonomy, and pest regulation. However, strategies currently used by farmers to recouple dairy livestock and crop production are poorly documented; there is a need to better assess these strategies using empirical farm data. In this paper, we employed farm surveys to describe, analyse and assess the following strategies: (1) Local exchange of materials among dairy and arable farms; (2) Land renting between dairy and arable farms; (3) Animal exchanges between lowland and mountainous areas; and (4) Industrially mediated transfers of dehydrated fodder. For each strategy, cooperating farm groups were compared to non-cooperating farm groups using indicators of metabolic performance (input autonomy, nutrient cycling and use efficiency), and ecosystem services provision. The results indicate that recoupling of crop and dairy production through farm cooperation gives farmers access to otherwise inaccessible or underutilised local resources such as land, labour, livestock feed or organic nutrients. This in turn leads to additional outlets for by-products (e.g. animal manure). Farmers’ decisions about how to allocate the additional resources accessed via cooperation essentially determine if the farm diversifies, intensifies or expands operations. The key finding is that in three of the four crop-livestock integration strategies assessed, these newly accessed resources facilitated more intensive farming practices (e.g. higher stocking rate or number of milking cows per hectare) on cooperating dairy farms relative to non-cooperating, specialised dairy farms. As a consequence, cooperation was accompanied by limited environmental benefits but helped to improve resource use efficiency per unit of agricultural product produced. This article provides a critical step toward understanding real-world results of crop-livestock cooperation beyond the farm level relative to within-farm crop-livestock integration. As such, it brings practical knowledge of vital importance for policy making to promote sustainable farming. 相似文献
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猪肺炎支原体主要抗原蛋白的研究进展 总被引：1，自引：1，他引：0
猪肺炎支原体(Mycoplasma hyopneumoniae,Mhp)是引起猪支原体肺炎(Mycoplasma pneumoniae of Swine,MPS)的病原,给养猪业造成巨大的经济损失。由于对具有良好免疫原性的Mhp特异性蛋白缺少深入研究,使得Mhp在致病机制、血清学检测方法和新型疫苗的研究发展上受到一定限制,从而影响了对MPS的控制。本研究综合Mhp主要粘附因子、膜蛋白及细胞质蛋白等主要抗原蛋白的研究进展,为该病原致病机理研究、建立特异性诊断方法和推动基因工程疫苗发展提供一定的理论基础,对MPS的正确诊断、检测、免疫预防和控制也有重要意义。 相似文献
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David Fangueiro Jos Pereira Joo Coutinho Nuno Moreira Henrique Trindade 《European Journal of Agronomy》2008,28(4):625-634
Farm-gate nutrient balances (N, P and K) were analysed in three groups of dairy farms from NW Portugal – medium, intensive and very intensive farms – during 3 consecutive years, 2003, 2004 and 2005. Results showed that the N surplus per hectare with values between 200 and 850 kg N ha−1 was positively correlated with the milk production per ha and the stocking rate of the farm, whereas the P and K surpluses showed fewer variations between groups. In all farms the main inputs were the mineral fertilizers and the feed concentrates whereas milk was the main output. Farmers involved in the study were advised in terms of nutrient management and significant decreases in the nutrient surpluses were observed during the 3 years study, mainly due to a decrease of the inputs, namely fertilizers. We conclude that advisory campaigns among farmers are efficient to reduce the nutrient surpluses. The N losses via NH3 emissions at farm scale were also estimated accordingly to IPCC emission factors and it appeared that such losses were significant and had to be considered together with the nutrient surpluses when strategies to enhance nutrient management are defined. On average, higher N surplus per hectare were observed in the studied dairy farms from NW Portugal relatively to other European regions, but NW Portugal present lower N surplus per production unit (kg milk) as well as higher N efficiency. Nevertheless, a target limit of 450 kg N ha−1 for N surplus should be easily reached as a first step by most of the farms of NW Portugal by improving nutrient management at farm scale. However, more efforts will be necessary to reduce NPK surplus and NH3 emissions to the mean values in a per hectare basis found in other European dairy regions with less intensive systems. 相似文献
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为了全面和准确地认识影响中国家庭农场成长的各因素及其权重,指导中国政府和家庭农场经营者采取最有效的措施培育和经营家庭农场,笔者首先基于资源基础理论和层次分析理论构建家庭农场成长影响因素的分析模型,然后以上海市松江区家庭农场为实证对象对各个因素进行计算和分析。结果表明：基于资源基础理论和层次分析理论所构建的家庭农场成长影响因素分析模型科学合理;一级因素中物质资本资源是现阶段影响家庭农场成长最主要的因素,其次是组织资本资源,人力资本资源现阶段相对较轻;二级因素中土地资本是影响家庭农场成长最重要的因素,其次是品牌优势、资金资本、基础设施和科学技术,其他因素有一定影响但在家庭农场的起步阶段相对较轻。最后,在该研究成果基础上,从政府和家庭农场经营者2个主体出发提出增加土地流转年限、积极打造品牌优势、拓宽家庭农场融资渠道、完善农业生产基础设施、引进先进科学技术等对策建议。 相似文献
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新疆拜城县和昭苏县集约化肉牛养殖场冬季环境指标比较研究 总被引：2，自引：0，他引：2
为比较新疆南北疆集约化养殖场冬季肉牛舍环境指标,本研究选择新疆阿克苏地区拜城县（南疆）和伊犁地区昭苏县（北疆）2 个集约化养殖场为对象,对其冬季肉牛舍光照强度、温度、湿度、噪音、CO2、NH3、CH4、PM10和TSP 等环境指标进行连续5 天08:00、12:00、18:00 和21:00 及3 天连续24 h 的测定,然后将2 个集约化养殖场数据进行比较。结果表明：拜城牛场光照强度、温度平均值及昭苏牛场温度、湿度平均值超出国家牲畜和家禽养殖场的环境质量标准(NY/T 388—1999)。此外,拜城牛场温度、湿度平均值极显著低于昭苏牛场(P＜0.01)。昭苏牛场CO2浓度超出NY/T 388—1999,CO2、NH3浓度平均极显著高于拜城牛场(P＜0.01)。上述环境指标连续24 h 变化表明,2 个集约化养殖场的温度都低于NY/T 388—1999;拜城牛场湿度52.7%~86.4%,全天有12 h 超出NY/T 388—1999,昭苏牛场湿度69.4%~97.4%,全天有18 h 超出NY/T 388—1999。拜城牛场CO2浓度为687.6~1799 mg/m3,在18:00 和19:00 超出NY/T 388—1999,昭苏牛场CO2浓度1459.6~3392.0 mg/m3,除05:00 时,其他时间都超出NY/T 388—1999。以上结果表明,南北疆冬季牛场环境指标存在较大差异,南疆拜城县牛场主要在于增加光照与保温,而北疆昭苏县牛场主要应该解决保温与改善圈舍空气环境的矛盾。 相似文献
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家庭农场是在“大国小农”的基础上实现农业现代化的重要载体和基础支撑。近年来,山东省家庭农场发展迅速但总体发展质量不高,在新经济时期的发展要求下,全面推进家庭农场向高质量发展方向转型具有重大意义。本研究在对山东省家庭农场支持政策梳理的基础上,对家庭农场的发展进行了阶段划分,结合相关统计数据,分析山东家庭农场发展的现状,对当前家庭农场高质量发展面临的突出问题加以总结。研究认为,当前土地流转困难、经营者综合素质有限、融资困难以及社会化服务体系滞后等问题是山东省家庭农场高质量转型的主要障碍。因此,要选择健全土地流转制度,推进农村人才激励培养机制,提供多元化政府补贴支持,增加政府服务供给、推动农业社会化服务体系发展等发展路径,全面推进家庭农场由增量向提质导向转型升级。 相似文献