奶牛乳腺的防御机制与乳腺炎病理学

乳头管的结构和内衬的角质蛋白是乳腺抵御微生物侵入的物理性屏障,角蛋白中的低级脂肪酸、阳离子蛋白质对侵入的病原微生物具有抗性;环境性致病菌是引起机体免疫应答的主要因子,巨噬细胞、单核细胞、中性粒细胞和淋巴细胞之间的相互协调组成了自然的免疫系统,它们通过分泌细胞因子、抗体和吞噬作用等活动来灭杀、清除侵入机体的病原体;乳中的可溶性因子具有免疫调节作用,对细菌的结构具有破坏性;妊娠期及围产期奶牛由于内分泌的变化而导致免疫抑制,结果造成临床型和亚临床型乳腺炎的发病率相对较高。     

畜禽传染病及其传播途径

畜禽传染病是指某种病原微生物(细菌、病毒或其它微生物)侵入畜禽机体后,使机体低抗力减弱而引起的具有一定潜伏期、临床表现和传染性的疾病。 传染病与非传染病相比较,有三个特点: 一、致病因子是活的病原微生物,当这种微生物侵入易感畜禽体内后,能使机体出现固有的临床症     

羊乳腺炎的临床症状及治疗措施

<正>羊乳腺炎通常由病菌侵入所引起,引起乳腺炎的病菌包括细菌、霉行体等20余种。90%的乳腺炎是由革兰氏阳性菌中的金黄色葡萄球菌和链球菌感染所致,其中以溶血性金黄色葡萄球菌,无乳链球菌危害最严重。这些病菌可单独感染,也可混合感染,病原微生物一般是通过乳头管或乳房的损失口侵入乳腺内,有时也可以经血管或淋巴管而感染。1主要症状1.1隐性型病羊不呈现临床症状,但乳中病菌及白细胞数较正常乳多,化学特征性也有改变。此类乳腺炎不     

奶牛乳腺炎无乳链球菌毒力相关因子

链球菌、金黄色葡萄球菌和大肠杆菌是引起奶牛乳腺炎的3大病原菌，在链球菌属中无乳链球菌是引起奶牛乳腺炎的重要病原菌之一，由无乳链球菌导致的乳腺炎约占隐性乳腺炎发病率的56.25%。无乳链球菌入侵奶牛乳腺的过程主要包括感染、黏附上皮细胞、侵入上皮细胞、损伤机体和免疫逃避等过程。无乳链球菌的毒力因子具有附着和侵袭机体细胞的作用，使菌体在奶牛乳腺表面形成生物被膜，进而干扰机体的正常免疫功能并引起疾病。本文主要阐述了无乳链球菌在入侵乳腺组织过程中发挥主要作用的毒力因子的种类、作用机制以及调控过程，旨在通过抑制其相关毒力因子的活性，从而阻断无乳链球菌在乳腺中感染和传播，进而为预防和治疗链球菌型乳腺炎提供新的思路。     

应用中药乳头灌注剂治疗临床型奶牛乳腺炎效果观察

<正>奶牛乳腺炎是一种由机械性刺激、病原微生物侵袭、化学物理性损伤所引起的炎症,包括两种基本类型,即临床型奶牛乳腺炎和隐性型奶牛乳腺炎。近几年,临床型奶牛乳腺炎发病率呈现出逐年上升趋势,严重影响奶制品质量,造成养殖户严重的经济损失。因此,选用合理的药物,防治临床型奶牛乳腺炎受到养殖户的普遍关注与重视。为探究临床型奶牛乳腺炎应用中药乳头灌注剂治疗效果,笔者以50头临床型奶牛乳腺炎病     

肠道粘膜免疫研究进展

肠道粘膜不仅是机体消化、吸收营养物质的场所，而且还具有重要的免疫功能。分泌型免疫球蛋白A、上皮内淋巴细胞、微皱褶细胞和细胞因子，共同组成肠道粘膜免疫系统，以阻止食物大分子和外来微生物抗原的侵入，保护肠道的结构和正常生理功能。     

乳头液体保护膜预防奶牛乳腺炎应用效果

<正>在奶牛乳腺炎患牛中,绝大部分是由外源性病原微生物感染引起的,病原主要是经乳头管口侵入乳腺组织而发生感染。因此,切断病原微生物的传播途径,是防止奶牛乳腺炎发生的最简单、有效、直接的方法。防止致病细菌感染的重点是消灭乳头口和乳头皮肤上的细菌,并在2次挤奶之间保护乳头,防止环境性致病细菌感染。目前,奶牛乳腺炎的预     

奶牛乳腺内微生物区系与乳房健康的关系研究进展

奶牛乳腺内的微生物变化与乳腺炎的发生、发展密切相关。近年来,随着高通量测序技术的不断更新,对微生物群落结构及功能的变化有了更全面及深入的认识。本文对奶牛乳腺不同部位的微生物变化与机体免疫及乳腺健康的关系进行综述,旨在阐明奶牛乳腺内微生物的重要作用,对更好地了解乳腺炎的发病机理具有重要意义,为治疗和预防乳腺炎提供了新的视角与机遇。     

奶牛乳腺炎的综合防控

<正>奶牛养殖中,乳腺炎为常见多发病,当乳腺组织受病原菌刺激而诱发的炎性疾病。可导致乳腺炎的菌种复杂,有黄色葡萄球菌、链球菌、大肠杆菌、化脓杆菌等。经病因分析,与病原菌侵入、环境因素、牛体状况等密切相关。根据临床症状的不同,奶牛乳腺炎可细分为急性型、慢性型和隐性型。为了确保奶牛养殖业的健康持续发展,必须做好该病的预防。1病因分析1.1病原菌侵入病原菌经乳头管口侵入,是乳腺炎发病率高的主要原因。     

乳酸菌与牛乳腺炎的相关性研究及应用

牛乳腺炎通常由病原菌微生物导致,是造成牧场损失最严重的疾病。临床上多采用抗生素方法治疗乳腺炎,但存在产生细菌耐药性、食品及生态安全等诸多弊端,且复发率较高。乳酸菌具有抑制病原菌、改善微生态环境和提高机体免疫力等优势,利用乳酸菌微生态制剂替代抗生素,用于奶牛健康养殖具有研究和应用价值。本研究对乳酸菌在牛乳腺炎中的生物多样性、作用机理和应用情况等方面做了论述,以期为今后研究乳酸菌防治牛乳腺炎提供借鉴。     

Prevalence of coagulase-negative staphylococci in bovine mastitis in Zimbabwe

This study was carried out to determine the prevalence of coagulase-negative staphylococci in clinical and subclinical mastitis in commercial and small-scale farms in Zimbabwe. Thirty five quarter milk samples from clinical mastitis cases and 371 quarter milk samples from cows with subclinical mastitis were cultured for bacterial pathogens. The most frequent pathogens isolated in clinical mastitis were the enteric bacteria (31.4%), followed by coagulase negative staphylococci (22.9%) and then Staphylococcus aureus (17.1%), whereas in subclinical mastitis S. aureus (34.2%) and coagulase-negative staphylococci were (33.2%) the most common. Bacillus species were only isolated in milk samples from subclinical mastitis. Coagulase-negative staphylococci were observed in mixed infections with other bacteria in only 2.2 of the 406 milk samples from clinical and subclinical mastitis where they were isolated together with Bacillus species in 6 of the 9 mixed infection cases. About 95% of the milk samples from which 131 coagulase-negative staphylococci were isolated had correspondingly high somatic cell counts. The coagulase-negative staphylococci isolated most frequently were S. chromogenes (7.9%), S. epidermidis (7.4%) and S. hominis (5.9%). They were all associated with high somatic cell counts. All the coagulase-negative staphylococci isolates were susceptible to cloxacillin and erythromycin, and more than 90% of the isolates were susceptible to neomycin, penicillin and streptomycin. The highest resistance was to tetracycline (17.6%), followed by lincomycin (13.7%). About 8% of the isolates were resistant to both penicillin and streptomycin.     

奶牛隐性乳房炎的流行病学调查及病原菌的分离鉴定

对某大型奶牛场进行隐性乳房炎的流行病学调查,以及致病菌的分离鉴定,结果得出:对同一牛舍76头泌乳牛进行CMT检测,其中隐性乳房炎的牛发病率为68.42%(52/76),在278个有效乳区中,隐性乳房炎的乳区有109个,乳区阳性率为39.21%(109/278),从10份被检乳汁中共分离出59株细菌,经生化鉴定其主要致病菌为金黄色葡萄球菌、无乳链球菌和大肠杆菌,分别占总数的18.64%。     

Concentration of serum amyloid A and ceruloplasmin activity in milk from cows with subclinical mastitis caused by different pathogens

The aim of the present study was to determine the concentration of serum amyloid A (SAA) and the activity of ceruloplasmin (Cp) in milk from cows with subclinical mastitis caused by different pathogens. Eighty-four milk samples from cows with subclinical mastitis and fourteen milk samples from healthy cows were examined. SAA concentration was determined using the commercial ELISA kit (Tridelta Development Ltd., Greystones, Wicklow, Ireland). Cp activity was assessed spectrophotometrically, using the Rice method. The results reveal that the concentration of SAA (with exception of CNS) and activity of Cp in cow milk can be regarded as markers of subclinical mastitis, irrespective of the microorganism inducing the disease. In conclusion, measurement of SAA and Cp in milk samples could be a useful method in diagnosing subclinical mastitis in cows, but the method should be adapted for field use.     

Acute phase proteins in milk in naturally acquired bovine mastitis caused by different pathogens

The concentrations of haptoglobin (Hp) and serum amyloid A (SAA) and the activity of N-acetyl-β-D-glucosaminidase (NAGase) in milk from 234 cows with spontaneous mastitis caused by different pathogens were measured to assess whether they corresponded with the clinical signs of mastitis and whether there were any differences between pathogens. Ninety-eight of the cows had clinical mastitis and 136 had subclinical mastitis. There were statistically significant positive correlations between the concentrations of SAA and Hp and the activity of NAGase. Significant differences in the concentrations of acute phase proteins and NAGase activity were found in milk from cows with mastitis caused by different pathogens. The highest concentrations of Hp and NAGase were found in cases of mastitis caused by Escherichia coli and Arcanobacterium pyogenes, and the lowest concentrations were from cases of mastitis caused by coagulase-negative staphylococci. Very low SAA concentrations were found in milk from the cases caused by A pyogenes, in contrast to cases caused by other major mastitis pathogens. The median concentration of SAA was over 10 times higher in cases of mastitis caused by E coli than in mastitis caused by other pathogens. There were significant differences in the mean Hp concentration and NAGase activity between clinical and subclinical mastitis. In approximately one-third of the samples, the Hp concentration was below the detection limit, potentially compromising the use of Hp as a mastitis marker.     

宁波市奶牛乳房炎发病及综合防治试验研究

为了解宁波地区奶牛乳房炎发病及主要病原菌构成,采用乳房炎诊断试剂(HMT)对宁波市8个奶牛场307头泌乳牛的1249个乳区进行了隐性乳房炎流行情况调查,采集HMT反应阳性(++)及强阳性(+++)乳区奶样进行细菌分离与鉴定;用纸片扩散法检测主要病原菌对常用抗菌药物敏感性,并选择具代表性牧场进行乳房炎综合防治试验。结果显示,宁波市奶牛隐性乳房炎的头阳性率为71.3%,乳区阳性率为33.5%。主要病原菌的检出率依次为:凝固酶阴性葡萄球菌47.1%、无乳链球菌20.4%、停乳链球菌17.3%、金黄色葡萄球菌5.1%和乳房链球菌3.9%。主要病原菌对青霉素、氨苄青霉素、庆大霉素、复方新诺明和链霉素等药物有不同程度的耐药性,对头孢类及苯唑青霉素敏感。综合防治措施的实施可以明显降低桶奶总细菌数,改善牛奶品质。     

奶牛乳腺炎的细菌学研究

在对山东7个地区14个奶牛场临床型和隐性乳腺炎调查的基础上采集234头临床乳腺炎病牛乳样、241个隐性乳腺炎乳样并分别做了细菌学检查,结果表明:泌乳期临床型乳腺炎病原菌以凝固酶阴性葡萄球菌、金黄色葡萄球菌、链球菌、酵母菌和棒状杆菌为主;干奶期临床型乳腺炎病原菌以大肠杆菌、链球菌、金黄色葡萄球菌、凝固酶阴性葡萄球菌和酵母菌为主;隐性乳腺炎病原菌以凝固酶阴性葡萄球菌、金黄色葡萄球菌链球菌、酵母菌、假单胞菌和棒状杆菌为主;厌氧菌在隐性乳腺炎、干奶期乳腺炎和干奶期乳腺炎乳样的捡出率分别为 5．82％,4．17%,10．16％;隐性乳腺炎、干奶期乳腺炎细菌的共感染率较高,与泌乳期乳腺炎病原菌的差异极显著(P<0．01),隐性乳腺炎与干奶期乳腺炎病原菌共感染率差异不显著(P >0．05)。     

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。     

Preliminary studies on the prevalence of Mycoplasma bovis mastitis in dairy in cattle in Australia

A highly sensitive and specific PCR (MB-PCR) was used in preliminary studies to detect M. bovis in milk samples to investigate its association with high somatic cell count (SCC), an indicator of subclinical mastitis and one of the factors in down grading the quality of milk. A total of 186 and 167 herds were tested with 43% and 62% of herds positive for M. bovis in Victoria and North Queensland, respectively. The quarter milks from 52 cows with persistently high SCC were tested by MB-PCR and culture to investigate the association of M. bovis with major mastitis pathogens (MMP). M. Bovis was detected in 77% of cows of which 19% alone had M. bovis without any other bacteria, 17% had M. bovis in combination with major mastitis pathogens and 40% had M. bovis in combination with non-major mastitis pathogens. We believe that M. bovis is widespread in dairy cattle and has the potential to produce disease alone or to predispose the udder to disease caused by major mastitis and environmental pathogens. These studies have revealed a hitherto unrecognised high prevalence of M. bovis in dairy cattle in North Queensland and Victoria in Australia. These initial studies also give a clear association between M. bovis and elevated somatic cell counts.     

Coagulase-negative staphylococci as cause of bovine mastitis- not so different from Staphylococcus aureus?

In this review of the literature, mastitis-causing coagulase-negative staphylococci (CNS) and Staphylococcus aureus are compared. Staphylococci are the bacteria most commonly isolated from bovine mastitis, and CNS are now predominant over S. aureus in most countries. CNS include various species, but only a few prevail in bovine mastitis. S. aureus can cause clinical mastitis, but often causes subclinical mastitis, which remains persistent and increases milk somatic cell count. CNS, traditionally regarded as minor pathogens, seem to lack the ability to cause severe mastitis. CNS can, however, persist in the mammary gland and moderately increase milk somatic cell count. Resistance to various antimicrobials is more common in CNS than in S. aureus, but CNS mastitis responds much better to antimicrobial treatment than S. aureus mastitis.     

Coagulase-negative staphylococci-emerging mastitis pathogens

Coagulase-negative staphylococci (CNS) have become the most common bovine mastitis isolate in many countries and could therefore be described as emerging mastitis pathogens. The prevalence of CNS mastitis is higher in primiparous cows than in older cows. CNS are not as pathogenic as the other principal mastitis pathogens and infection mostly remains subclinical. However, CNS can cause persistent infections, which result in increased milk somatic cell count (SCC) and decreased milk quality. CNS infection can damage udder tissue and lead to decreased milk production. Staphylococcus simulans and Staphylococcus chromogenes are currently the predominant CNS species in bovine mastitis. S. chromogenes is the major CNS species affecting nulliparous and primiparous cows whereas S. simulans has been isolated more frequently from older cows. Multiparous cows generally become infected with CNS during later lactation whereas primiparous cows develop infection before or shortly after calving. CNS mastitis is not a therapeutic problem as cure rates after antimicrobial treatment are usually high. Based on current knowledge, it is difficult to determine whether CNS species behave as contagious or environmental pathogens. Control measures against contagious mastitis pathogens, such as post-milking teat disinfection, reduce CNS infections in the herd. Phenotypic methods for identification of CNS are not sufficiently reliable, and molecular methods may soon replace them. Knowledge of the CNS species involved in bovine mastitis is limited. The dairy industry would benefit from more research on the epidemiology of CNS mastitis and more reliable methods for species identification.