母犬的异常发情

受生理、营养、疾病、年龄等因素影响,母犬往往会异常发情。如不能及时发现,将会延误配种。现将母犬常见的几种异常发情的原因及防治措施介绍如下：     

A Simple and Rapid PCR‐Based Method for Ostrich Sexing Using Micro Amounts of DNA

The aim of the present study is to identify ostrich sex by using polymerase chain reaction (PCR) on micro amounts of DNA from blood, bloodstain and feathers. Sixteen male and 18 female ostriches were used as test individuals. Genomic DNA as a template was extracted by the Chelex method. Ostrsex‐P1 and P2 primers were designed to perform PCR amplification on the template. PCR products were checked using agarose gel electrophoresis with ethidium bromide staining and ostrich sex was determined directly by the bands shown on the gel. The results demonstrate that ostrich sex can be determined by the extraction of DNA from as little as 0.0125 μl blood using Chelex, whereby the use of large amounts of organic solvents such as phenol and chloroform are unnecessary. In addition, it is possible to identify ostrich sex using micro amounts of DNA extracted from bloodstains and/or feathers. The use of feathers particularly avoids unwanted sampling problems such as the difficulty of collecting ostrich blood, the stress to the ostrich caused by bleeding, and the demand for a lot of manpower for ostrich restraint.     

猪场常见繁殖系统疾病的临床区别诊断

布氏杆菌病、细小病毒感染、猪繁殖与呼吸障碍综合征(PRRS)、猪瘟、猪伪狂犬病、猪乙型脑炎、猪附红细胞体病、衣原体、猪钩端螺旋体及饲料霉菌毒素中毒都共同出现流产症状,同时也有很多不同点。本文根据临床经验,将其归纳整理,系统地比较各病之间的不同点,为临床兽医正确区别诊断这类疾病提供宝贵的经验。     

不同品系杜洛克后代商品猪胴体性状的比较分析

为研究不同品系杜洛克作为终端父本对其后代商品猪胴体性状的影响,选取214和108头分别由美系和加系杜洛克公猪配种、出生时间相近(±2 d)和体重相近(35±5 kg)的后代三元商品猪进行育肥饲养,结束饲养后开展屠宰试验,测定背膘厚度、眼肌厚度、瘦肉率和肋骨数.结果显示:加系杜洛克商品后代的背膘厚度、眼肌厚度显著(P<0...     

H9亚型禽流感病毒钦州株HA基因的克隆与遗传进化

采集钦州活禽交易市场的鸡气管和泄殖腔的棉拭予样品,用H9亚型分型引物进行PCR初步筛选,阳性样品经SPF鸡胚尿囊腔接种分离病毒,通过RT-PCR方法扩增HA基因,并将其克隆到pMD—18T载体后进行序列测定和分析。结果表明,获得1株H9亚型禽流感病毒命名为：A／Chicken／Guangxi／qz40／2009（简称qz40）。测序结果表明qz40的HA基因片段全长1683bp,编码560个氨基酸;序列同源性比较结果表明,该毒株与参考毒株的核苷酸序列同源性为82．8％．99．9％,推导氨基酸同源性为87．5％．99．6％;HA基因的裂解位点氨基酸顺序为RSSRIGLF,为低致病性毒株;含有7个潜在的N-糖基化位点,其中5个位于HAl部分、2个位于HA2部分;基于H9亚型HA基因的进化树分析表明,qz40株属于欧亚种系的A／Chicken／Beijing／1／94（Ck／Bei—like）群系。     

鳖典型性肿脖子病的病因学研究

１材料与方法１．１临诊症状病鳖反应迟钝,行动缓慢,常伏在饲料台、晒台或产卵床上,颈部有明显的周围隆起,中间凹陷的疮痂病灶。病灶四周组织红肿,皮肤腐烂,表皮坏死,可成块脱落,造成脖子局部肿大,但头颈部仍可伸缩。有些病鳖前肢还有烂爪现象。发病中后期,可见...     

家蚕黑尾病及其防治方法研究

家蚕黑尾病主要是由曲霉菌在蚕尾部寄生引起的一种真菌病 ,从病蚕中分离到病原菌有两种 ,一种孢子表面棘多而长、黄褐色 ,孢子大 ,直径 4～ 6 μm ;一种孢子表面棘短而少、蓝绿色 ,孢子小 ,直径 2～ 3μm。黑尾病在高温多湿条件下多发 ,多发生于 4龄中期至 5龄中期。黑尾病病原菌侵染寄生家蚕的过程是 :病原菌分生孢子附着在蚕尾部背板与节间的三角形节间膜处 ,分生孢子发芽侵入蚕体产生黑色小病斑 ,随病情加重病斑加大 ,甚至在病斑处出现节间断裂 ,直至形成黑尾症状。使用药剂防治黑尾病以 5 %亚迪蚕保最佳     

Characterization of polymorphisms of transferrin receptor and their association with susceptibility to ETEC F4ab/ac in pigs

Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.