某新建大型奶牛场临床乳房炎病原菌分离及发病规律

对我国南方地区某新建大型奶牛场2010年10月至2012年7月间头胎及二胎共2006头荷斯坦牛临床乳房炎发病情况进行调查，结合病原菌感染类型结果，用x^2检验分析不同胎次临床乳房炎发病次数和发病率及不同致病菌导致的临床乳房炎在不同季节和泌乳阶段发病率的差异。结果表明，该牛场一胎和二胎奶牛临床乳房炎发病率分别为11．81％和9．02％（按头数算），但二胎牛多次发生临床乳房炎的比例较大。一胎奶牛仅发现大肠杆菌和葡萄球菌单独感染及葡萄球菌一大肠杆菌混合感染3种病原菌组成类型，二胎奶牛比头胎牛增加了金黄色葡萄球菌、链球菌、酵母菌和链球菌一葡萄球菌混合感染4种类型。致病菌类型以大肠杆菌和葡萄球菌单独感染为主，一、二胎奶牛均占总发病数85％以上；季节和泌乳阶段对一、二胎奶牛临床乳房炎发病率具有显著影响（P〈0．05），一胎牛秋季发病率最高，而春季发病率最低，而二胎牛冬季发病率最高（33．33％），秋季最低（16．88％）；2个胎次奶牛泌乳早期临床乳房炎发病率明显高于其他阶段。大肠杆菌和葡萄球菌在整个泌乳期均可发生，酵母菌主要出现在二胎牛泌乳中期，平均感染时间分别为（148．75±69．60）d，而金黄色葡萄球菌和链球菌主要发生在二胎牛泌乳后期，平均感染时间分别为（213．60±55．88）和（234．43±42．35）d。结果对该地区同类型奶牛场临床乳房炎防控有重要的参考价值。

The incidence bovine of clinical mastitis and isolation of its pathogenic bacteria in a new large dairy farm

The incidence rate of clinical mastitis was investigated for 2 006 first and second lacta- ting Holstein cows in a new large dairy farm in south China from October 2010 to July 2012. Com- bining the type of pathogen infection, the number and incidence rate of clinical mastitis due to dif- ferent pathogenic in different seasons and stage of lactations for different parity were analyzed by ）2 test. The results showed that incidence rate of clinical mastitis of first and second lactation cows were 11.81% and 9.02% ,respectively （by the number of cow）. Multiple onsets of clinical mastitis cases in the second lactation were more than those of first parity. Three types of patho- gens included Escherichia coli, Staphylococci and mixed infection of the two bacteria were found in the first lactation cows. Four types of pathogens included Staphylococcus aureus, Streptococ- cus, Saccharomycetes and mixed infection of Staphylococcus and Streptococcus added in the second lactation compared with first lactation. The proportion of clinical mastitis were deterted infected alone by Escherichia coli and Staphylococcus was more than 85% in first and second lactation cows. Season and stage of lactation had significant effects on the incidence of clinical mastitis in both of the first and second lactation cows（P〈0.05）. Incidence of clinical mastitis in first laetation was the highest in autumn,and was the lowest in spring. However,incidence of clinical masti- tis in second lactation was the highest（33.33%）in winter,and was the lowest（16. 88%） in au tunm. The incidence of clinical mastiffs in pro-phase of the lactation was higher than other stages. The clinical mastitis infected alone By Escherichia coli and Staphylococcus was found throughout the lactating period. The clinical mastitis infected by Saccharomyceles occurred in recta-phase of second parity cows, and the average infecting time was（148.75 ±69.60）days. The clinical mastitis infected by Staphylococcus aureus and Streptococcus occurred mainly in post-phase of second lac- tation cows,and the average infection time was（213.60±55.88）days and（234.43±42.35）days, respectively. These results had important value for the prevention and control of clinical mastitis in the same area and type of dairy farms.