新城疫为什么防不住

<正>无论是蛋鸡养殖还是肉鸡养殖,新城疫可以说是最应引起重视的疫病:新城疫的疫苗品种及数量是最多的,免疫程序中免疫次数也是最多的,每次鸡病技术培训及专家研讨,新城疫也是必讲的,但我们看到的结果却是:临床病例中新城疫的发病率最高,它给养鸡业造成的损失从某种意义上说也最大。新城疫是一个老病,几乎年年讲、月月讲,所     

不同类型鸡新城疫的诊断与防制措施

鸡新城疫一直是影响我国养鸡业健康发展的主要疾病之一，也是相关人员研究防治的重点。随着免疫措施的不断尝试和加强，鸡新城疫的流行特点也发生了相应的变化。根据生产实践中新城疫的发病特征，可将新城疫归纳为典型新城疫、非典型新城疫和高致病性新城疫。     

规模鸡场新城疫的防制策略

新城疫是由新城疫病毒引起的鸡多病型高度接触性传染病。该病一般分典型和非典型新城疫。该病传染快、发病急,经常在养殖场间大流行。新城疫的发生常与病毒毒力、鸡群抗体水平、鸡群日龄密切相关。超强毒一般是嗜内脏型、强毒一般是神经型、中等或低毒力的常引发非典型新城疫。抗体水平的高低也影响新城疫发生类型,如抗体水平低下,常发生典型新城疫;抗体水平高则常发生非典型新城疫。     

鸡新城疫发病原因的综述

目前虽然国家对新城疫的防控十分重视,然而由于养禽业的快速发展,集约化养殖越来越多,家禽产品的运输范围越来越大,使得新城疫的传播也越来越难以控制,鸡群新城疫的发病也越来越频繁。虽然鸡场会对鸡群进行新城疫免疫,但由于新城疫病毒毒株变异快,不同毒株毒力也并不相同,因此非典型新城疫的出现也就不可避免。本文对新城疫的发病原因进行讨论,希望能减少鸡新城疫疫情的发生。     

鸵鸟新城疫诊断及防制策略

1鸵鸟新城疫流行现状新城疫是当前危害和威胁养禽业最严重的传染病之一,由于新城疫在鸵鸟中感染率很高,各种年龄的鸵鸟均易感,因此许多国家都把新城疫列为法定预防的传染病。鸵鸟新城疫于1989年首次发生在以色列。上世纪90年代突然出现走禽的国际贸易的异常繁荣,导致在世界范围走禽疾病也突然增加,在1998～2000年间,在贸易的巅峰时期,新城疫传遍了南非等国家的鸵鸟群。1992年之后,我国成为鸵鸟进口大国,陆续从非洲大量进口鸵鸟,新城疫也同时在鸵鸟群中出现严重流行。1997年刁有祥、王春敖等首次报道我国发生鸵鸟新城疫流行,并从发病及死亡的…     

鹧鸪几种常见病的防制

一新城疫 在禽类中,鸡最易感染,鹧鸪也能感染.新城疫是由新城疫病毒侵入鹧鸪体内而引起的一种急性败血性传染病,主要通过消化道和呼吸道感染.     

鸡非典型新城疫的防制：鸡非典型新城疫的原因分析及预防对策

新城疫（ND）作为危害当前我国养鸡业的一种主要疾病之一，日常生产中养殖户虽然广泛使用各种新城疫活疫苗和灭活疫苗，免疫密度和频次也远远超过世界水平．但新城疫（特别是非典型新城疫）仍时有发生，并给养殖户造成严重损失，非典型新城疫已经成为养禽业的第一杀手。     

新城疫病毒结构蛋白功能及检测技术研究进展

新城疫是一种由新城疫病毒引起的烈性传染病,病死率很高,严重危害家禽养殖业,被世界动物卫生组织列为必须报告的动物传染病。在我国,新城疫的暴发和流行虽然已得到了控制,但病毒的变异给新城疫的防控工作带来了困难。新城疫病毒的隐性感染也对我国禽类产品的质量及出口造成了一定影响。因此,明确新城疫病毒各结构蛋白的功能、改进现有检测技术以及开发新的检测技术平台是目前新城疫防控工作的重点。论文对新城疫病毒结构蛋白功能及检测技术的进展进行了系统的阐述。     

新城疫疫苗的研究进展

新城疫是由新城疫病毒引起的一种烈性病毒性传染病．是当今全球范围内重要的家禽传染病之一，目前。新城疫在全国范围内的发生仍然比较普遍。对于该病的控制，接种疫苗仍是主要手段，Allan曾对新城疫的免疫接种和疫苗产品等作了详细报道，同时，对于利用免疫接种控制新城疫，Meulmans也有详细论述。现笔者对世界上现有的几种主要新城疫疫苗的研究进展介绍如下。[第一段]     

鸵鸟新城疫的流行现状和防控

正新城疫在鸵鸟中感染率很高,各种年龄的鸵鸟均易感,鸵鸟新城疫于1989年首次发生在以色列。1992年之后,我国成为鸵鸟进口大国,陆续从非洲大量进口鸵鸟,新城疫也同时在鸵鸟群中出现严重流行。鸵鸟新城疫的发生和流行与其他禽类所流行的新城疫,以及频繁的国际贸易有着非常密切的联系。近年来我国北方地区鸵鸟的养殖量不断增加,鸵鸟新城疫也时有发生。     

电感耦合等离子-质谱法测定饲料中钠、镁、铬、锰、铁、铜、锌、砷、硒、镉和铅

应用电感耦合等离子-质谱技术(ICP-MS),建立饲料中钠、镁、铬、锰、铁、铜、锌、砷、硒、镉和铅等元素的测定方法。对饲料样品的前处理方法、仪器工作参数和11种元素标准曲线进行优化;并以加标回收、分析方法比对和重复测试说明方法的准确性和精密性。方法在0～1 000 ng/ml范围内线性良好,仪器检出限为0.557 7～5.072 ng/ml,具有良好的精密度,其回收率在88.1%～104.4%之间,相对标准偏差小于5.0%。同时与原子吸收和原子荧光方法进行比对,测定结果相近。所建立的方法简单、快速,可替代原子吸收和原子荧光方法测定饲料中的11种金属元素,为饲料的质量控制提供理想的元素分析方法。     

Supplementation of broodmares with copper, zinc, iron, manganese, cobalt, iodine, and selenium

In experiment 1, 6 pregnant mares received a concentrate that contained a trace mineral premix that provided 14.3 mg Cu, 40 mg Zn, 28 mg Fe, 28 mg Mn, 0.08 mg Co, 0.16 mg I, and 0.16 mg Se/kg concentrate (group A). Seven mares received the same concentrate plus 502 mg Zn and 127 mg Cu once daily (group B). No differences (P > .05) in foal growth data, or Cu, Zn, and Fe concentrations of mare milk, mare serum, or foal serum were observed. In experiment 2, 6 pregnant mares received the same concentrate as group A (group C), and 8 mares received the same concentrate fortified with 4× the trace mineral premix (group D). Group C mares had higher serum Zn concentration at 1 day (P < 0.01) and 56 days (P < 0.04). Group C mares had higher milk Fe concentration at 28 days (P < .01), and group D mares had higher milk Cu concentration at 56 days (P < .01). Group C foals had higher serum Cu concentration at 14 days (P < .03). The results from this study provide no evidence to indicate that supplementing late gestating and lactating mares with higher dietary trace mineral levels than those recommended currently by NRC has any influence on foal growth and development, or on the Cu, Zn, and Fe concentrations of the mare milk, mare serum, or foal serum.     

Comparisons of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, and Shorthorn breeds for weight, weight adjusted for condition score, height, and condition score of cows

Breed differences for weight (CW), height (CH), and condition score (CS) were estimated from records (n = 12,188) of 2- to 6-yr-old cows (n = 744) from Cycle IV of the U.S. Meat Animal Research Center's Germplasm Evaluation (GPE) Program. Cows were produced from mating Angus and Hereford dams to Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires. Samples of Angus and Hereford sires were 1) reference sires born from 1962 through 1970 and 2) 1980s sires born in 1980 through 1987. The mixed model included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation code (PL), and breedgroup as fixed effects for CW and CS. Analyses of weight adjusted for condition score included CS as a linear covariate. The model for CH excluded PL. Random effects were additive genetic and permanent environmental effects associated with the cow. Differences among breed groups were significant (P < 0.05) for all traits and were maintained through maturity with few interchanges in ranking. The order of F1 cows for weight was as follows: Charolais (506 to 635 kg for different ages), Shorthorn and Salers, reciprocal Hereford-Angus (HA) with 1980s sires, Nellore, HA with reference sires, Galloway, Piedmontese, and Longhorn (412 to 525 kg for different ages). Order for height was as follows: Nellore (136 to 140 cm), Charolais, Shorthorn, Salers, HA with 1980s sires, Piedmontese, Longhorn, Galloway and HA with reference sires (126 to 128 cm). Hereford and Angus cows with reference sires were generally lighter than those with 1980s sires. In general, breed differences for height followed those for weight except that F1 Nellore cows were tallest, which may in part be due to Bos taurus-Bos indicus heterosis for size.     

液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量的不确定度评估

采用液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量,对标准溶液、体积、质谱峰面积、浓缩过程及回收率等测定不确定度因素进行了分析,通过评定各不确定度分量及标准不确定度,得出11种β-受体激动剂的扩展不确定度在0.7 ～ 1.1 ng/mL范围内.由各因素对合成不确定度的贡献比分析可知,影响较大的因素为试验回收率及标准溶液浓度.