奶牛难产激发应激性急性肾上腺皮质功能不全——心衰、水电解质严重失调辩析     

邱立和  陈贵喜  李宏全 《山西农业大学学报(自然科学版)》1992,(2)

应激性急性肾上腺皮质功能不全症的病理机制十分复杂,目前人医的各类文献中大都以“垂体—肾上腺轴”功能不全、功能衰竭、或发生广泛性出血坏死性病演作解释。本病在奶牛分娩难产过程中并不少见,病牛的症状表现以心衰和失钠性低血症为主征。但在兽医临床上由于认识不足,曾有不少中外学者将奶牛产后卧地不起的各类疾病,含糊地统称为“母牛睡倒爬不起来综合征”;更由于救治不当,病牛常以淘汰或死亡告终。本文通过对一具体典型病例辨析,着重讨论了本病的基本病理反应和确立诊断依据,强调对本病救护施治时应遵循的基本原则,供同道们在分析和解决这一实际问题时参考。  相似文献   

Growth loss of Lebanon cedar (Cedrus libani) stands as related to periodic outbreaks of the cedar shoot moth (Dichelia cedricola)     

Serdar Carus  Mustafa Avcı 《Phytoparasitica》2005,33(1):33-48

An outbreak ofDichelia cedricola (Diakonoff) (Lep.: Tortricidae), the cedar shoot moth (CSM), began in spring 1998 and lasted 3 years. This was the first monitored outbreak of the CSM in Isparta, Turkey. Tree crowns recovered to near normal condition by the middle of each growing season (in early June) during the outbreak. Tree volume and volume element increments were examined throughout the outbreak cycle from 1954 to 2001. In the past, CSM activity in stands of Lebanon cedar (Cedrus libani A. Rich.) was assessed through radial increment analyses. Cedar tree ring chronologies were analyzed for evidence of the CSM. Tree-ring chronologies from nonhost cedar (nondefoliated sample trees) were used to estimate potential growth in the host cedar (defoliated sample trees) during current and past outbreaks; all trees selected were the same subspecies and varieties. Regional outbreaks of the CSM were identified by synchronous and sustained growth periods of the trees. In 2001, increment cores were collected from 17 host and 16 nonhost dominant or codominant trees and annual radial growth indices from 1954–2001 were calculated for each of two host and two nonhost sample plots. Growth functions were defined as the cumulative sum of radial, height, and volume increment, and were graphically compared between CSM host cedar and nonhost cedar trees. Tree ring evidence suggests that a large-scale outbreak occurred in 1955 (from 1955 to 1966) and a small outbreak occurred in 1985 (1985–1990) and in 1998 (1998-continued) in the study area. The average diameter growth reductions around 1955, 1985 and 1998 were 40%, 46% and 7% of potential, respectively. It was concluded that a narrow latewood band is significant indicator of defoliation by the CSM and the outbreaks appear to be associated with dry winter and spring weather prior to the autumn and winter in which wood feeding occurred. http://www.phytoparasitica.org posting Nov. 24, 2004.  相似文献   

旱地保护性耕作地表径流和土壤水分平衡模型   总被引：12，自引：3，他引：12  

王晓燕  高焕文  李洪文 《干旱地区农业研究》2003,21(3):97-103

在田间试验和对现有径流模型及土壤水分平衡模型改进的基础上，建立了适用于保护性耕作的地表径流和土壤水分平衡模型。该模型以日为步长，根据气象数据、土壤水分状况、作物生长发育及耕作管理措施，模拟不同耕作管理体系下地表径流和田间水分平衡的变化。针对保护性耕作的特点，主要对径流曲线数字(USDA—Curve Number)法进行了改进，在PERFECT模型的基础上增加了坡度和降雨强度两因素的影响，从而使模型较全面地考虑了残茬覆盖、耕作、坡度及降雨强度等多种因素对径流的影响；采用简单实用的Priestley—Taylor公式计算潜在蒸散量，并考虑作物覆盖与残茬覆盖对土壤蒸发与作物蒸腾的影响。通过田间径流试验和根层有效贮水量测定数据的验证，证明了地表径流和土壤水分的模拟值与实测值比较接近。  相似文献   

Biological and Physical Constraints on Maize Production in the Humid Forest and Western Highlands of Cameroon     

Z. Ngoko  K.F. Cardwell  W.F.O. Marasas  M.J. Wingfield  R. Ndemah  F. Schulthess 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(9):893-902

The aim was to identify biological and physical factors responsible for reducing maize yield in Cameroon. Two surveys were conducted in 137 fields in two agroecological zones in 1995–1997. In the Humid Forest (HF), Bipolaris maydis, Stenocarpella macrospora, Puccinia polysora, Rhizoctonia solani and soil fertility were factors that reduced maize production in 1995 and 1996. In the Western Highlands (WHL), Cercospora zeae-maydis, and the interaction between soil fertility and maize variety were the most important constraints to maize production in 1996. In 1997, C. zeae-maydis, S. macrospora, physiological spot and stem borer damage (Busseola fusca) were negatively related to ear weight. The combination of these biological factors (diseases and insects), and the physical parameter of soil fertility were responsible for reducing maize yield in these selected benchmarks of Cameroon. Maximum potential yield reductions were estimated at 68% due to B. maydis and 46% due to S. macrospora, respectively, in the HF in 1995. In 1996, maximum potential yield reductions in the HF were estimated at 34%, 41% and 30% due to S. macrospora, P. polysora and R. solani, respectively. In the WHL, C. zeae-maydis had the potential to cause a yield reduction of 79% in 1996. In the WHL in 1997, the interaction between C. zeae-maydis and B. fusca, stem diseases and the physiological spot caused potential reductions of 52%, 34% and 39%, respectively.  相似文献   

稻象甲的防治指标和防治适期研究   总被引：2，自引：1，他引：2  

黄水金  秦厚国  张华满  刘福秀  刘剑青 《植物保护》2002,28(3):12-15

根据稻象甲虫量与水稻产量的关系 ,结合现行的稻谷价格 ,产量水平和防治费用等因素 ,进行了稻象甲危害损失的测定 ,制定了稻象甲的防治指标。采用累积虫日作为防治指数 ,确定了在江西境内稻象甲的防治适期  相似文献   

茭白纹枯病发生规律及产量损失测定   总被引：5，自引：0，他引：5  

徐强  梁继农  曹碚生  江解增 《植物保护学报》2002,29(2):114-118

茭白纹枯病发生规律与产量损失的研究结果表明:高温高湿、种植过密、偏施氮肥、缺乏钾素是病害加重的主要原因;田间发病盛期在7月中旬至8月中旬;单茭重减低率与病级之间呈极显著线性相关;始病期越早,危害越重,产量损失也越大;病害危害程度与有效分蘖数(孕茭数)减少率、单茭重减低率、产量损失率之间呈高度正相关。在产量损失构成中,有效分蘖数的减少为主要因素。  相似文献   

全球气候暖干化对秦岭南北河流径流泥沙的影响研究   总被引：8，自引：12，他引：8  

查小春 《干旱区研究》2002,19(3):62-66

以秦岭南侧汉江和北侧渭河多年的径流泥沙观测资料，分析了全球气候暖干化对秦岭南北径流泥沙的变化。分析指出在80年代后，由于全球气候变化的影响，秦岭南北河流年均径流量均减少，与1935－1980年相比，汉江河流年均径流量减少1.9%，渭河河流年均径流量减少27.4%；同时汉江河流泥沙含量明显减少，但渭河河流泥沙含量呈增加趋势，是汉江河流泥沙含量133倍，表明了秦岭南北两侧在全球气候暖干化表现出明显的区域响应性。  相似文献   

喀喇昆仑山盖孜河水文水资源特性分析   总被引：2，自引：1，他引：2  

李燕  李红斌  王连有 《干旱区研究》2003,20(4):272-275

喀喇昆仑山河流自有水文资料记载以来 ,近 10年洪灾发生频率明显高于以往 ,人民的生命财产损失程度也大幅度增加。在分析了盖孜河流域的径流及气候多年变化过程后 ,认为洪灾频发的原因是近年来流域内降水及气温呈上升趋势 ,导致高山冰川退缩 ,河流径流增加 ,洪灾增大、频率增高 ;小区域多年气候变化过程从侧面印证了我国西北地区气候由暖干向暖湿变化。  相似文献   

夏大豆成熟期害鼠防治指标的研究     

潘学锋  刘同群 《中国植保导刊》1997,(2)

夏大豆成熟期害鼠防治指标的研究潘学锋（安徽省霍邱县植保站２３７４００）刘同群（霍邱县城西湖乡农技站）摘要本文通过大田调查夏大豆田的害鼠发生种类及其密度与产量损失的关系，结果表明，沿淮地区夏大豆田的害鼠种类为黑线姬鼠、黑线仓鼠、褐家鼠、小家鼠等，其中以...  相似文献   

优质牦牛肉肉质的综合评价   总被引：8，自引：0，他引：8  

冶成君 《青海畜牧兽医杂志》2004,34(4):18-19

2000-2002年对大通牛场40头6月龄不同性别的全哺乳牦牛的肉质进行了综合评价。对供试牦牛肌肉pH、嫩度、肌纤维细度、系水率、肉的贮存损失、肉的煮熟时间、熟肉率和烹饪损失率及肉色等进行了评价，分析了肌肉的化学成分，氨基酸及微量元素含量。结果表明该牦牛肉系水率强，肉的煮熟时间短，肉的贮存损失及烹饪损失较小，肌纤维较细，肉色深红。并具有蛋白质含量高，脂肪含量低及富含各种氨基酸的特点。  相似文献