禽流感疫苗免疫失败的原因分析

笔者在日常技术服务过程中常会遇到诸如“为什么免疫了禽流感疫苗,我的鸡群仍然会发生禽流感疫情”等问题。严格来讲,禽群免疫相关疫苗后仍然发生该传染病属于免疫失败的范畴。本文对禽群免疫禽流感疫苗后仍然发生疫情的原因进行了粗略分析。     

动物接种疫苗发生不良反应的原因

<正>疫苗对动物机体的刺激可发生正常生理反应和非正常的病理反应,这些都是动物机体的生物学效应,机理相对复杂,通常情况下,动物由于接种疫苗出现副反应的原因主要归结为三个:即疫苗质量、机体及操作等原因。1疫苗原因1.1疫苗质量问题在疫苗制备过程中,外源病原污染常常导致副反应发生,如猪瘟活疫苗中污染了猪瘟强毒病源,当接种这种疫苗时就会出现猪瘟疫情。另外灭活疫苗由于抗原灭活不全,接种此类疫苗也会导致疾病发生。     

动物疫苗规范管理初探

畜牧业发展离不开动物疫苗,疫苗规范化管理显得尤为重要,为了避免动物疫苗在贮存使用过程中发生错误操作,笔者根据多年疫苗管理与使用经验,对动物疫苗规范化管理谈几点看法,仅供大家参考。     

禽用多联灭活苗的制配及应用

目前我国市场上家禽疫苗的种类非常多,有活疫苗、灭活疫苗;有单苗、联苗、基因工程疫苗等,因此如何选择和使用疫苗对控制疫病发生十分重要。禽用多联灭活疫苗是种鸡和蛋鸡养殖过程中最为常用的疫苗品种。     

禽用多联灭活苗的制配及应用

目前我国市场上家禽疫苗的种类非常多,有活疫苗、灭活疫苗;有单苗、联苗、基因工程疫苗等,因此如何选择和使用疫苗对控制疫病发生十分重要。禽用多联灭活疫苗是种鸡和蛋鸡养殖过程中最为常用的疫苗品种。     

猪注射猪瘟疫苗后的副反应及控制措施

疫苗对控制猪病具有重要作用,但在使用疫苗过程中过分夸大其作用,认为只有疫苗才能对病猪进行防治,也没有根据疫病发生地区的实际条件,按照相关程序进行综合治理,从而影响了猪的健康状况。本文对猪注射猪瘟疫苗后的副反应进行分析,并阐述其发生的原因,利用相关措施予以控制,为相关人员提供参考。     

口蹄疫的免疫机理及其疫苗过敏反应的处理措施

在进行口蹄疫免疫的过程中,经常遇见由口蹄疫疫苗引起的过敏反应,若处理不及时可引起免疫动物的死亡,造成一定的经济损失。主要对口蹄疫的免疫机理、疫苗过敏反应发生机理、口蹄疫疫苗过敏反应临床症状与处理措施以及预防措施作一介绍,以期为更好地避免口蹄疫疫苗过敏反应的发生提供参考。     

猪用疫苗的免疫方法及注意事项

随着养猪业的发展,集约化和规模化的养殖在一定程度上加剧了疾病的发生,人们在猪病防治过程中采取了很多措施,包括药物预防,改善饲养条件,疫苗免疫等等,其中免疫接种具有见效快,易实施等特点。随着人们对免疫接种意识的提高,疫苗免疫的方法和细节变得尤为重要,本文将对养猪过程中疫苗的免疫方法及免疫过程中注意事项做简单介绍。     

讯息快递

台湾将香蕉当做PRRS疫苗台湾大学报道他们已经研究出转基因香蕉可作为猪繁殖与呼吸综合征的疫苗。他们研发出一种新的口服疫苗,有了这种疫苗,猪可以采食,而且很方便,此外,还减少了烹饪过程中,疫苗蛋白发生继发感染或弱化的风险。据报道,使用基因工程技术将病毒的遗传物质转到香蕉的染色体上,香蕉就可作为生物反应器,变成了天然的口服疫苗。这项专利已经在我国内地、台湾地区和美国获得认证。     

畜禽免疫失败的原因调查及应对措施

在生产实践中,畜禽接种疫苗后免疫效果不佳或出现免疫失败的情况时有发生,给畜禽疫病防控带来一定的困难.主要从疫苗质量、疫苗稀释过程、免疫程序、接种途径、免疫操作、疫苗间的干扰作用及药物干扰等方面分析了导致免疫失败的原因,并提出了相应的应对措施,以期为有效预防免疫失败的发生提供参考.     

Mechanisms underlying Phalaris aquatica "sudden death" syndrome in sheep

Twenty outbreaks of Phalaris aquatica "sudden death" syndrome in sheep were investigated between 1981 and 1991. Four were confirmed and one was suspected, to be a cardiac disorder; 5 were confirmed and 3 were suspected, to be a polioencephalomalacic disorder; the aetiology of the remaining 7 outbreaks could not be determined. Potentially toxic levels of hydrocyanic acid (20 to 36 mg/100 g) were measured in the 3 toxic phalaris pastures tested. The measurement of potentially toxic levels of nitrate nitrogen (2920 micrograms/g) in toxic phalaris pastures by others, was noted. It is suggested that phalaris "sudden death" syndrome could have as many as 4 different underlying mechanisms, and that these might reflect the presence in the plant of a cardio-respiratory toxin, a thiaminase and amine co-substate, cyanogenic compounds, and nitrate compounds.     

"Candidatus Mycoplasma haemominutum" infections in 21 client-owned cats

Medical records were reviewed for 21 clinically ill cats testing positive for deoxyribonucleic acid (DNA) of "Candidatus Mycoplasma haemominutum" in their blood. Fever, anorexia, lethargy, and anemia were among the most common abnormalities recorded. Thirteen cats were anemic; seven had evidence of other diseases that could have been the primary cause of anemia or activated hemoplasmosis. For six cats, "Candidatus Mycoplasma haemominutum" was the only recognizable cause of the anemia. Of these cats, anemia resolved in one cat without treatment and in three cats that were treated with doxycycline, with or without prednisone. Results of the study suggest that this hemoplasma species can be a primary pathogen in cats.     

“香连”溶液干膏剂体外抑菌试验研究

本试验旨在探讨中草药体外抑菌作用,为纯中草药消毒剂的临床使用和扩大临床使用范围提供科学依据。本试验以金黄色葡萄球菌、大肠杆菌、沙门氏菌为模式菌株,以抑菌圈直径、抑菌浓度、细菌生长曲线和抑菌温度曲线为检测指标,研究纯中草药消毒剂"香连"溶液干膏剂的抑菌活性。试验结果显示,对3种模式菌株的抑杀效果由强到弱依次为金黄色葡萄球菌、大肠杆菌、沙门氏菌,MIC分别为7.81、31.25、250mg/mL,所需时间分别为2、2、6h,对金黄色葡萄球菌、沙门氏菌抑杀环境温度为25、37℃。结果表明,"香连"溶液消毒剂不仅可作为环境消毒剂,也可作为饮水消毒剂和细菌性疾病的治疗药物。     

Studies on effect of lighting on "Sudden death syndrome" in broiler chickens.

Broiler chicken flocks were studied to determine the mortality from sudden death syndrome occurring in the flocks. The difference in the incidence of the syndrome in pullets and cockerels, and the age at which the most birds are affected were also studied. The weight of sudden death syndrome birds was compared with the flock average and the effect of continuous lighting as opposed to intermittent lighting was examined.The results suggest that; continuous lighting produces more sudden death syndrome deaths than intermittent lighting; that the incidence of sudden death syndrome is higher in cockerels than pullets; that the highest death rate occurred during the third and fourth weeks of life, and that sudden death syndrome birds on the average were heavier than the flock average.     

Normal reproductive parameters in large "California-style" dairies

Reproductive parameters are important in evaluating modern dairy management performance. Successful dairying results from constant attention to daily events, requiring more sensitive and immediate measurements of performance. Definitions of formulas, numerators, denominators, and population included or excluded are essential for proper interpretation and comparison of results. Veterinarians understanding these statistics and indexes, and using stratification of data to investigate production losses, will serve their clients well. My advice is to approach a herd with a perceived reproductive problem by evaluating these parameters; they are the means of determining if a problem exists and, if so, where it is. Find out how the various parameters are calculated so your interpretation will be correct. Herds with average days in milk of less than 165, culling rates below 25 per cent, and a milking rate of 85 per cent or more do not have long-term reproductive problems. If management techniques fail to achieve these levels, first look at those areas involving people. Conception rates measure all the components that, when multiplied, equal fertility: insemination technique, semen quality, heat detection accuracy, and the cow factors involved. Poor conception rates require investigation into these areas individually. Heat detection intensity leading to prolonged days in milk at first service is another common finding. Comparison of inseminators and sires may identify a problem area. Cow factors require more intense investigation to determine their cause. Use the information outlined in the periparturient period to assist you. In most cases, a combination of failures in many of the independent factors creates the problems in reproduction that we encounter. A large data base including all the information discussed and additional information is necessary to define, correct, and monitor reproductive management performance. Since performance ultimately is determined by the quality of the labor force, ongoing monitoring for accountability and education is necessary for success.     

Chronic "Candidatus Mycoplasma turicensis" infection

"Candidatus Mycoplasma turicensis" infects felids. The pathogenesis of "Candidatus M. turicensis" chronic infection is poorly understood. The goals of the present study were to (1) induce reactivation of the infection in chronic carrier cats by attempted immunosuppression, (2) identify potential tissue sequestration using real-time TaqMan^® PCR and (3) monitor the humoral immune response by DnaK enzyme-linked immunosorbent assay (ELISA). Ten specified pathogen-free cats that had ostensibly recovered from experimental "Candidatus M. turicensis" infection were used: five cats (group 1) received high dose methylprednisolone (attempted immunosuppression), while five cats served as untreated controls (group 2). Besides weekly blood samples, tissue samples were collected from bone marrow, kidney, liver and salivary glands at selected time points. The cats in group 1 had significantly lower lymphocyte counts and higher blood glucose levels after methylprednisolone administration than the controls. After methylprednisolone administration one blood and three tissue samples from cats in group 1 tested PCR-positive; before the administration, only one sample was positive. All other samples tested PCR-negative. All cats stayed seropositive; the antibody levels of the cats in group 1 showed a significant transient decrease after methylprednisolone administration. This is the first study to report the presence of "Candidatus M. turicensis" in tissues of chronically infected cats and the persistence of anti-feline hemoplasma antibodies in the absence of detectable bacteremia. Methylprednisolone administration did not lead to a significant reactivation of the infection. Our results enhance the knowledge of "Candidatus M. turicensis" infection pathogenesis and are clinically relevant to the prognosis of hemoplasma-infected cats.     

“乳宁散”对小鼠急性和大鼠亚慢性毒性的试验研究

通过小鼠急性毒性试验和大鼠亚慢性毒性试验评价防制奶牛隐性乳房炎中药"乳宁散"的安全性。将"乳宁散"制备成相当于原药材1.0 g/mL的水煎提取浓缩液,选取50只小鼠,随机分为5组,以5000、7500、10000、15000 mg/kg体重的剂量1次灌胃给药,观察中毒症状,记录死亡数和计算半数致死量(LD₅₀);另取40只小鼠,随机分为2组,给药组以最大浓度(1.0 g/mL)、最大容积(0.04 mL/g)1次灌胃受试药物,对照组用等体积生理盐水,给药后连续观察7 d,测定最大给药量;再取80只大鼠,随机分成药物处理高、中、低剂量组和对照组,药物组按大鼠体重3000、1500和750 mg/kg剂量灌胃给药,连续30 d,对照组用生理盐水,检测大鼠体重、血常规指标、血液生化指标、脏器系数及组织病理变化情况。结果表明,急性毒性试验各剂量组均无小鼠死亡,无法计算LD₅₀,经口给药的最大剂量为40.0 g/kg体重,表明该产品实际无毒;亚慢性毒性试验中,药物处理组大鼠体增重、血常规、血液生化指标和脏器系数与对照组相比无显著差异(P>0.05),组织病理学观察实质器官无异常病变。提示,临床合理使用中药"乳宁散"不会对靶动物产生毒性作用。     

"Subclinical" laminitis in dairy cattle

In dairying countries worldwide, the economic importance of lameness in cattle is now recognised. Laminitis is regarded as a major predisposing factor in lameness caused by claw disorders such as white zone lesions, sole ulcer, and heel horn erosion. The existence of subclinical laminitis was first suggested in the late 1970s by Dutch workers describing the symptoms of sole haemorrhages and yellowish-coloured, soft sole horn. In an attempt to clarify some of the confusing and often conflicting terminology, the literature on laminitis is reviewed. Disturbed haemodynamics, in particular repeated or prolonged dilation of arteriovenous anastomoses, have been implicated in the pathogenesis of both equine and bovine laminitis. Some characteristics of the vascular system of the bovine claw which may be of importance in the pathophysiology of the subclinical laminitis syndrome are therefore discussed. Clinical observations suggest that subclinical laminitis is a multifactorial disease. The different factors that are or may be involved in its aetiology vary in complexity and severity according to the management protocol of the animals. The possible involvement of subclinical laminitis in claw lesions is assessed.     

青海地区燕麦“3414”施肥效果及推荐施肥量

合理的施肥是提高燕麦(Avena sativa)产量的主要措施之一。以‘青引1号’为试验材料,于2012-2014年采用"3414"施肥方案,研究不同氮(N)、磷(P)、钾(K)配施对青海地区燕麦种子产量及经济效益的影响,旨在为青海地区燕麦的合理施肥提供依据。结果表明,不同氮、磷、钾配施处理下燕麦的产量和经济效益均高于不施肥处理,以处理N2P3K2的产量最高,达到4 785.2kg·hm-2,较不施肥处理增产1 488.9kg·hm-2,而处理N2P2K0可增收3 324.7CNY·hm-2,其增收效果最为明显;两两互作对燕麦产量的影响表现为NPNKPK。燕麦施肥量与产量间的一元二次方程拟合结果均典型,能够较好地反映施肥量同产量的关系,但在氮磷施用量中等水平时,随着钾肥施用量的逐渐增加,燕麦产量开始降低,因此,青海地区燕麦种植可不施用钾肥;通过氮磷的二元二次拟合方程可得出,本研究条件下获得燕麦最高产量的施肥方案为氮118.6kg·hm-2、磷177.0kg·hm-2,产量可达4 867.4kg·hm-2,纯收入为12930.9CNY·hm-2。最佳经济施肥方案为氮102.2kg·hm-2、磷102.0kg·hm-2,产量为4 731.3kg·hm-2,纯收入为13 111.6CNY·hm-2。     

复方中药对鸡蛋胆固醇含量的影响

用0.5%复方中药降胆增蛋灵作蛋鸡饲料添加剂,连续饲喂180日龄海兰褐蛋鸡30d,对供试鸡血液、蛋成分进行了测定和分析。结果表明,降胆增蛋灵可降低鸡血液甘油三酯（TG）、总胆固醇（TC）含量;增高血清高密度脂蛋白胆固醇（HDL-C）、总蛋白（TP）、白蛋白（ALB）、球蛋白（GLO）含量、HDL-C/TC值、碱性磷酸酶（AKP）和卵磷脂胆固醇酰基转移酶（LCAT）活性。降低鸡蛋胆固醇和总脂含量分别以16%和20%,提高鸡蛋蛋白质和钙含量分别为15.2%和15.0%,增加产蛋率12.3%,提高了蛋壳硬度,减少了鸡蛋破损率,加深了蛋黄色泽。表明降胆增蛋灵是降低鸡蛋胆固醇较为理想的添加剂。