Adiponectin links adipose tissue function and monocyte inflammatory responses during bovine metabolic stress

The periparturient period of dairy cows is characterized by intense lipid mobilization from adipose tissue leading to increased plasma concentrations of nonesterified fatty acids (NEFA). High NEFA are a predisposing factor for inflammatory based diseases. A major component of these diseases is uncontrolled macrophage/monocyte inflammatory responses. Changes in the endocrine activity of adipose tissue during the periparturient period could impact macrophage function by modifying the secretion of adipokines including adiponectin. Currently, the effects of adiponectin on monocyte activation in dairy cattle are unknown. In humans and rodents, this adipokine regulates monocyte phenotype and alterations in its plasma levels are linked with the development of inflammatory diseases. The objectives of this study were to establish associations between plasma adiponectin expression dynamics and different markers of lipid mobilization during the periparturient period of dairy cows and to characterize the effects of adiponectin on the inflammatory response of bovine monocytes. Plasma adiponectin, NEFA, BHB, albumin, and subcutaneous and retroperitoneal fat depots depth were measured during the periparturient period of dairy cows. In vitro, bovine monocytes were cultured with adiponectin to assess changes in pro-inflammatory responses following LPS stimulation. Results from this study demonstrate that alterations in plasma adiponectin levels in periparturient cattle are inversely correlated with the concentrations of plasma NEFA, an important marker of lipid mobilization. Furthermore, adiponectin exposure significantly decreased monocyte expression of TNFα after LPS stimulation thus markedly reducing their inflammatory response. Reduced plasma adiponectin during the periparturient period could predispose dairy cows to the development of uncontrolled monocyte inflammatory responses.     

奶牛四种流产性疾病的流行现状及疫苗研究进展

奶牛布氏杆菌病、传染性鼻气管炎、病毒性腹泻-黏膜病及新孢子虫病是导致我国奶牛流产发病比例升高的主要疾病,有效防控这四种疾病一直是世界关注的重点之一。本文对上述四种疾病的流行现状及疫苗研究进展进行了综述。     

Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high‐producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk‐meter and vacuum shut‐off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum.     

牛传染性鼻气管炎病毒gD基因表达质粒免疫小鼠的试验研究

基因疫苗是近几年来发展起来的一种新型疫苗，具有使用安全，生产、运输、贮存方便，免疫效果稳定持久的特点。实验采用PCR方法将从洛阳种牛场西门塔尔牛精液中分离的牛传染性鼻气管炎(Infectious bovine rhino—traeheitis virus，IBRV)洛精株gD基因进行了扩增，经序列测定确证后构建了gD基因的真核表达质粒。将其单独或连同脂质体肌肉注射于BALB／c小鼠，应用ELISA定期检测血清抗体水平。结果表明，含IBRV gD基因的表达质粒能够引起小鼠的特异性血清抗体反应。     

我国牛源金黄色葡萄球菌耐药现状及药敏检测方法探讨

为调查我国牛源金黄色葡萄球菌的临床耐药现状,对2009年以来新疆、浙江、山东、内蒙古和上海五省区不同地方分离的120株金黄色葡萄球菌用纸片扩散法进行临床药敏试验。结果显示,新疆分离株对红霉素、克林霉素、青霉素、复方新诺明、多西环素、四环素耐药,22%的菌株对头孢西丁耐药,43%的对氯霉素耐药,64%的对环丙沙星耐药,58%的对庆大霉素耐药;其它4地区分离株耐药情况更为严重,除头孢西丁以外,对其它9种抗生素均耐药。对菌株的多重耐药情况分析发现,新疆分离株中对5种以上抗生素耐药的占86.1%,对10种抗生素完全耐药的占17.4%;而内地分离株的数据为100%和38.2%。此外,在试验中鉴定出33株耐甲氧西林金黄色葡萄球菌,新疆19株,占新疆菌株的22.1%,内地四地区14株,占内地分离株的41.2%。结合2005~2009年间发表的相关耐药数据的分析结果,研究显示,我国牛源金黄色葡萄球菌呈现多重耐药,且出现了耐甲氧西林金黄色葡萄球菌,并在不同地区分离株中占有一定的比例;研究还发现,新疆分离株与浙江、山东、内蒙古和上海四地分离株的耐药情况有较大差异。此外,在整理药敏试验资料时,发现在金黄色葡萄球菌药敏试验中,药物的选择没有遵循选药规则,试验操作不规范和试验结果的报告不规范等问题,对此提出一些探讨性建议,供试验人员参考。     

牛卵泡抑素基因克隆及真核表达载体构建

[目的]克隆牛的卵泡抑素基因（Follistatin,FSTN）基因,构建真核表达载体。[方法]用Trizol法从牛的卵巢中提取总RNA,反转录成cDNA,用带有酶切位点牛FSTN的特异性引物扩增其完整编码区序列,连接到T载体、测序,序列无误后亚克隆入真核表达载体pIRES2-AcGFP1中,酶切及PCR鉴定载体。[结...     

牛呼吸疾病综合征及其防治

牛呼吸疾病综合征是严重危害国内外肉牛养殖业的一种重要传染病,该病的致病因素复杂,包括支原体、病毒和细菌等特异性病原以及运输应激等多种因素。美国等发达国家对该病的攻关研究开始于上世纪80年代初,其研究和临床防控均已达到较高水平,但仍认为该病将是未来10～20年养牛业所面临的主要疾病。我国对该病的认识和研究尚处于起步阶段,借鉴世界上发达国家的先进经验将有助于提升我国对该病的防控水平。     

Molecular detection of BHV-1 in artificially inoculated semen and in the semen of a latently infected bull treated with dexamethasone

Two polymerase chain reaction (PCR) assays specific for glycoprotein B (gB) and glycoprotein E (gE) gene detection, respectively, were adopted for the detection of bovine herpesvirus-1 (BHV-1) in naturally infected bulls. The methods were tested on bovine semen artificially inoculated with BHV-1 and were compared with an optimised virus isolation method. Raw and extended semen samples were diluted in minimal essential medium (MEM) and spiked with equal dose of BHV-1. The extended semen was found to be more toxic for the cells than the raw semen, while the viral DNA could be detected by the PCR method in all tested dilutions of raw and extended semen samples. The sensitivity of both methods was compared also for BHV-1 detection in semen, nasal swabs and leucocytes of a seropositive bull in a different time period after virus reactivation with dexamethasone treatment. The sensitivity of virus detection by the PCR method was equivalent to that of virus isolation in cell culture. However, PCR was shown to be faster and easier to perform and may be a good alternative to virus isolation especially when bovine semen has to be screened for BHV-1 prior to artificial insemination.     

昆明市奶牛隐性乳房炎流行状况调查

奶牛隐性乳房炎发病率高、流行广,是导致奶业经济损失最大的疾病。为了解昆明市奶牛场隐性乳房炎的流行状况,采用加州乳房炎检测法(CMT)对昆明市周边3个标准化奶牛场和3个奶牛合作社奶牛按照30%比例进行随机抽样检查。在抽检的2 297份乳样中,隐性乳房炎阳性数为897份,阳性率为39.05%,规模化奶牛场的隐性乳房炎阳性率(28.79%)显著低于奶牛合作社(56.21%)(P<0.01);奶牛后乳区发病率(69.34%)明显高于前乳区(57.64%);随着产犊胎次的增加,奶牛乳房炎患病率随之显著增高。本调查对掌握昆明地区奶牛隐性乳房炎的发病情况,以及早发现和控制该病发生、提高牛奶质量具有重要的指导意义。     

凉州区奶牛乳房炎主要病原分离鉴定及药敏试验

乳房炎是奶牛最常见的疾病,随着奶牛产业的蓬勃发展,乳房炎已经成为制约该产业的瓶颈之一。从甘肃省武威市凉州区5个奶牛养殖场采集了1 000头荷斯坦奶牛共计3 991份奶样,对临床型和非临床型(隐性)乳房炎分别通过临床症状和兰州隐性乳房炎诊断液(LMT)进行诊断。结果显示:该地区奶牛临床型乳房炎发病率18.20%,亚临床型乳房炎发病率36.50%,总阳性率54.70%,总阳性乳区率54.72%。从阳性奶样中分离纯化得到的主要病原菌为链球菌属、金黄色葡萄球菌和大肠杆菌,且在不同类型乳房炎中的分布情况不同,临床型中链球菌属最多(54.37%),亚临床型中金黄色葡萄球菌最多(48.56%)。对主要病原菌进行药敏试验,结果表明治疗凉州区奶牛乳房炎的最佳药物应为喹诺酮类和庆大霉素类。