恩诺沙星及其代谢产物在奶牛乳中的消除规律

 【目的】研究乳房炎奶牛单剂量乳房灌注1%恩诺沙星（50 ml/头）后乳中药物浓度的变化规律。【方法】采用HPLC法测定乳中恩诺沙星及其代谢产物环丙沙星的浓度,用统计矩原理处理药物浓度—时间数据。【结果】在给药区恩诺沙星和代谢产物环丙沙星均于给药后2ｈ左右乳中浓度达到最高值,分别为（13.16±3.10）μg?ml-1和（2.79±0.94）μg?ml-1,然后逐渐下降;12 ｈ后检测不到恩诺沙星,24 ｈ已检测不到环丙沙星。对于非给药区,恩诺沙星给药后1ｈ左右乳中浓度达到最高值（0.19±0.02）μg?ml-1,然后逐渐下降;6 ｈ后检测不到恩诺沙星,而代谢产物环丙沙星于给药后4 ｈ乳药浓度可达最高峰（0.51±0.07）μg?ml-1,24 ｈ已检测不到乳药浓度。给药区代谢物环丙沙星的消除半衰期较恩诺沙星长,平均为（1.67±0.20）h,平均滞留时间（MRT）亦长。在本试验条件下,建议临床休药期不少于3 d。【结论】恩诺沙星吸收较迅速 ,代谢较快、清除较快 ,表明恩诺沙星与环丙沙星在乳中不会形成残留。     

两种病原菌联合诱导大鼠实验性乳腺炎研究

为深入研究奶牛乳腺炎提供一个更方便、经济的实验平台,试验建立了由金黄色葡萄球菌和大肠杆菌联合诱导的大鼠乳腺炎模型。分别用低浓度(金黄色葡萄球菌和大肠杆菌浓度均为1×105mL-1,L组)和高浓度(金黄色葡萄球菌和大肠杆菌浓度均为1×1012mL-1,H组)细菌混合液,经乳头管灌注到大鼠第4对乳腺内,诱导大鼠的乳腺炎试验。结果表明,低浓度组(L组)乳腺的病变主要以腺泡上皮发生轻度脂肪变性,腺泡腔的分泌物中有透明滴状物为主要特征,高浓度组(H组)的乳腺腺泡结构破坏严重,腺泡中有较多的嗜中性粒白细胞浸润。L组乳腺组织IL-6水平较对照组有所升高,H组则有显著(P<0.05)下降,试验组血清IL-6水平均极显著(P<0.01)低于对照组;L组和H组乳腺组织TNF-α水平分别显著(P<0.05)和极显著(P<0.01)高于对照组,血清TNF-α水平均极显著(P<0.01)低于对照组。试验组乳腺NAGase活性均显著(P<0.05)和极显著(P<0.01)高于对照组;试验组血清NAGase活性均低于对照组,其中H组极显著(P<0.01)下降。由上述结果可知,高低浓度的金黄色葡萄球菌和大肠杆菌联合诱导的大鼠乳腺炎模型均已成功建立。     

哈尔滨地区奶牛隐性乳房炎病原菌的分离鉴定

通过BMT法、乳汁pH检验法和体细胞直接计数法等方法相结合,对哈尔滨市3个大型奶牛场、10户奶牛养殖户选取的1 000头奶牛,4000个乳区进行隐性乳房炎的流行病学调查,以及致病菌的分离鉴定.结果表明,其中隐性乳房炎的发病率为47.7%(477/1 000);乳区发病率为27.3%(1092/4000),从477头的隐...     

Mycoplasma leachii causes bovine mastitis: Evidence from clinical symptoms,histopathology and immunohistochemistry

Twelve quarters of six lactating cows were inoculated with Mycoplasma leachii strain GN407 through intramammary ductal infusion; another 12 quarters were inoculated with heat-inactivated M. leachii culture medium as negative controls. Multidisciplinary procedures, including clinical assessment, etiology assessment, pathology and immunohistochemistry (IHC), were used to elucidate the pathogenicity of M. leachii in bovine mastitis. From post-inoculation days (PIDs) 3 to 9, 12 inoculated quarters developed mild to severe clinical mastitis and mammary tissue histopathological changes, including inflammatory cell infiltration and architectural destruction of mammary gland ducts. The M. leachii antigen was also detected by IHC in the mammary gland epithelial cells of the inoculated quarters as a weak signal on PID 6 and as a strong signal on PID 9. The control quarters also developed mild mastitis and histopathological changes on PID 9, and M. leachii was also detected by IHC. Throughout the experimental period, the quarters of the negative control cow were clinically and pathologically normal, and the M. leachii antigen was not detected. In conclusion, direct histological and immunohistochemical evidence confirmed that M. leachii causes clinical bovine mastitis through histopathological lesions induced by invasion of the pathogen into mammary gland cells and through inflammatory cell infiltration.     

急性临床型奶牛乳房炎病原菌的分离鉴定与药敏试验

本文对一起群发性急性临床型奶牛乳房炎进行了病原分离鉴定、致病性及药敏试验,结果表明该乳房炎是由金黄色葡萄球菌、停乳链球菌和铜绿假单胞菌混合感染引起,其中金黄色葡萄球菌和铜绿假单胞菌对小鼠表现出较强的致病性,三株菌对兽医临床常用抗生素均表现出较强的耐药性。     

Diagnosis and treatment of mastitis in mares

Infection and inflammation of the udder (mastitis) is a common condition affecting all domestic mammals, but it appears to be less prevalent in mares than in dairy cows and dairy goats. The seemingly reduced incidence of mastitis in mares can be partially explained by the smaller size and relatively concealed location of the mare’s udder, coupled with a smaller storage capacity than cows and goats. Mastitis can affect lactating, peripartum, dry mares, mares at dry-off or prepubertal foals. Common clinical signs include swollen mammary tissue, abnormal mammary gland secretion, fever and anorexia; less common signs are hindlimb lameness and a swollen mammary vein. On rare occasions, mastitis pathogens can severely affect the nursing foal and mares may develop fibrotic tissue and consequent agalactia in the side(s) or quarter(s) affected. Based on the clinical presentation, mastitis can be classified as acute or chronic, and clinical or subclinical. Diagnosis is based on the clinical signs aided with aerobic culture and cytological evaluation of the gland secretion. In addition, these ancillary tests can also be used to assess prognosis and duration of treatment. Mares suffering from mastitis may present neutrophilia and hyperfibrinogenaemia. Treatment for mastitis includes antimicrobial therapy (systemic and/or locally), nonsteroidal anti-inflammatory drugs, frequent milking and cold hosing with/without hot-packing applied on the gland. While the frequent monitoring of mares after weaning and reducing food intake should be part of common practices at weaning, cleaning of the udder, control of insect populations and frequent milking of mares with a foal unable to nurse can also aid in preventing mastitis.     

Study on Clinical Efficacy of Oligosaccharide Sulfate and Dextran Sulfate Against Bovine Mastitis

In order to detect the clinical efficacy of oligosaccharide sulfate(DEAE) and dextran sulfate (DS-4000) against bovine mastitis,56 cows with bovine mastitis were divided into 5 groups (DEAE group,DS-4000 group,DEAE＋penicillin group,DS-4000＋penicillin group and penicillin group),and their breasts were perfusion with different drugs twice one day for 3 days.The effective rates of drugs were observed by clinic symptoms.Milk samples were collected before and after treatment of drugs,and the bacterial negative conversion rate of each group were detected by microbial examination.The results showed that total effective rates of 5 groups were 10.00%,20.00%,58.33%,75.00% and 50.00%,respectively,and the bacterial negative conversion rates were 0,12.50%,50.00%,54.55% and 44.44%,respectively.In conclusion,the curative efficiencies of the polysaccharides against bovine mastitis were weak,but it could be improved by combination with penicillin.     

Isolation and Identification of Pathogenic Bacteria Causing Dairy Cow Mastitis in Liaoning and Drug Sensibility Test of Pathogenic E.coli

In order to understand the main bacterial pathogen species causing dairy cow mastitis in Liaoning, as well as the characteristics of drug sensitivity of the pathogenic E.coli,the milk samples from 75 dairy cows with clinical manifestations for mastitis in certain large-scale dairy farm in Liaoning were collected.The bacteria in milk were cultured and isolated with biochemical methods and in vitro drug sensitivity tests were processed with the isolated E.coli strains.The results showed that the main bacterial pathogen for dairy cow mastitis were E.coli（separation rate 58.7%),S.aureus（64.0%）and S.agalactiae（54.7%),and multiple infection including double and triple infection were identified.The drug sensitivity tests on the isolated E.coli indicated that the E.coli isolates were highly resistant to sulfonamides（resistance rate>85%）and chloramphenicol（resistance rate>30%),and they were relatively low resistant to ampicillin（9.5%),ciprofloxacin（9.5%),ceftiofur（7.1%）and ofloxacin（4.8%).The results was able to provide reliable theoretical basis for prevention and control of dairy cow mastitis in Liaoning area.     

奶牛乳铁蛋白基因PCR-RFLP与隐性乳房炎的相关性分析

采用CMT方法检测奶牛的乳房炎发病情况,筛选120头分别设为对照组(健康奶牛)、隐性乳房炎组(试验组),每组60头,用限制性片段长度多态性(RFLP)分析技术,检测乳铁蛋白(Lf)基因启动子区域的RFLP多态性。结果表明:不同组别的奶牛Lf基因启动子区域存在RFLP多态性,说明该多态性与乳房炎存在一定关系。