Cause & Pathogenesis 無乳鏈球菌—革蘭氏陽性球菌Streptococcus agalactiae – gram-positive cocci · 高度傳染，專性奶牛乳腺寄生細菌
Highly contagious obligate inhabitant of mammary gland of cow
擠奶時牛—牛傳播 Cow to cow transmission at milking
不侵入乳房組織，但損害上皮
Does not invade mammary tissue but does damage epithelium
危險因素
Risk Factors
帶菌牛只 Carrier cows
不正確的擠奶程序 Improper milking procedure
臨床癥狀
Clinical Findings
主要引起亞臨床性乳房炎Mainly causes sub-clinical mastitis
乳無可視變化 No visible changes in the milk
所有乳房炎病例的90%是亞臨床性乳房炎（70%的經濟損失來自乳房炎）
90% of all cases of mastitis are sub-clinical (70% of financial loss from mastitis)
在所有的成年泌乳奶牛中，亞臨床性乳房炎是最昂貴的疾病
Sub-clinical mastitis is the most expensive disease of adult dairy cows
體細胞計數高 High Somatic Cell Count (SCC)
可偶爾發作成臨床性乳房炎May occasionally flare-up to clinical
體溫升高，食欲下降，精神萎靡，奶有變化
Elevated temperature, decreased appetite, depression and changes in the milk 診斷
Diagnosis· 根據SCC，臨床癥狀和乳的細菌培養
Based on SCC, clinical signs and milk culture 鑒別診斷
Differential Diagnosis
其他原因引起的乳房炎 Other causes of mastitis
實驗室和病理學診斷Laboratory and Pathology · 如果牛群有問題，大批乳桶的SCC升高
If herd problem, elevated bulk tank SCC · 引起單個感染牛只的SCC顯著升高
Causes marked increase of SCC in individually infected cows · 利用SCC鑒別感染牛，然后用CMT鑒別感染乳區
Utilize SCC to identify infected cows then use CMT to identify infected quarter
肯定感染乳區做細菌培養以區分其他鏈球菌和葡萄球菌
Culture infected quarter-must differentiate from other Streptococcus and Staphylococcus 治療
Treatment· 無乳鏈球菌對抗生素敏感，包括青霉素
Streptococcus agalactiae is sensitive to antibiotics including Penicillin · 在泌乳期，用Blitz治療所有感染牛
Blitz treat all infected cows during lactation
預后情況
Prognosis· 治療有效的，預后良好，可從牛群中消滅
Good for response to treatment and elimination from the herd 預防
Prevention & Control
阻止傳播是基本的預防措施Stopping transmission is the basis of control擠奶程序和衛生設備
Milking Procedure and Sanitation
Clean and stimulate milk letdown with individual paper towels 4. 如果清洗，在洗液中加消毒劑
Disinfectant in wash solution if used 5. 只洗臟的奶牛，洗后必須完全擦干
Only wash dirty cows then must be thoroughly dried
擠奶員戴橡膠手套
Rubber gloves on milker
應用奶杯
Apply milking claw 從程序2至7應有60—90秒
Time from 2 to 7 should be 60 to 90 seconds
避免過度擠奶 Avoid over-milking
浸泡乳頭可以傳送排乳信號
Teat dip post milking · 檢驗并套上擠奶器 Test and maintain milking machines · 在干乳期，每頭奶牛的每個乳區都要干燥 Dry cow treat every quarter of every cow at dry off · 淘汰慢性感染牛只 Cull chronically infected cows · 治療所有的臨床性乳房炎病例 Treat all cases of clinical mastitis · 隔離所有的感染牛只及其牛乳 Isolate all infected cows and milk last · 擠感染牛奶后，要消毒奶杯 Sterilize clusters after milking infected cows · 保持一個封閉的牛群 Maintain a closed herd