الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In this study Four hundred (400) milk samples were examined from El-Dabiba Vet Clinic (200 cows) and smallholders in Sadat city area (200 cows) during one year from December 2011 to November 2012 to detect cases of mastitis. Clinical mastitis cases were detected in 41 cases (20.5%) by clinical examination (inflammation of udder- pain in touch- edema- and/ or abnormalities in milk) and 64 cases (32%) of subclinical mastitis cases were detected by CMT.
The clinical signs observed on mastitic cows were systemic reaction in the form of fever, depression and anorexia in 10 cows signs of acute inflammation of the udder (hotness, swelling, hardness and pain) and changes in milk, in the form of (bloody milk and flakes) when examined by strep cup test in 21 cows . Atrophy and fibrosis as signs of chronic inflammation was recorded in 10 cows with watery and thick pus in milk .All animals showed reduction in milk production.
CMT was used for detection of subclinical mastitis. Of theses 64 samples were positive with different degree of mastitis. Weak Positive (+) means distinct precipitation with no gel formation was found in 15 samples (23.4%), medium Positive (++) means that the milk was thickened with some suggestions of gel formation was in 22 samples (34.4%) and strong positive (+++) means Gel formation and the mass tends to adhere to the Bottom of the cup was found in 27 samples (42.2%).
Bacteriological examination of 105 matitic milk samples showed that only 65 samples were positive in bacteriological cultured (61.9%), while 40 samples were negative cultures. The total number of isolates from positive cultured samples was 79 isolates. Staphylococcus aureus is the most prevalent isolates of mastitis in clinical and sub clinical mastitis cases in which 23 isolates from clinical mastitis cases (29.11%), and 17 isolates from sub clinical mastitis cases (21.51%). This is followed by streptococcus Species in which 13 isolates (16.5%), 16 isolates (20.2%), were isolated from clinical and sub clinical mastitis cases respectively. Six isolates of Pseudomonas Species (7.6%) were reported only from sub clinical mastitis cases. One isolate (1.27%) of both E.coli and Enterobacter species was recovered from clinical mastitis and the same in subclinical mastitis.
Multiplex PCR was used for identification of bacterial causes of mastitis from the isolated bacterial culture and directly from the milk samples without the need for culture step. A single DNA band of 229 bp detected for Staph. aureus by using specific primers targeting 16s-23s ISR rRNA genes was detected. Detection of 16 S rRNA genes as shown at a band 561 bp confirming the Streptococcus Species. The detection of tra T gene is clear by 313 confirm the isolation of E.coli.
It is clear from this study that 47 (44.76%), 29 (19.73%) and 29 (19.59%) were recoded in early stage, middle stage and late stage respectively. Statistical analysis showed highly significant effect between mastitis and stage of lactation.
The highest prevalence of mastitis in cows was found at Fifth lactation numbers & over in 37 samples (49.33%) followed by third lactation number in 27 samples (25.71%). The lower percentage was found at fourth lactation season in 13 samples (15.29%) the first and second lactation number revealed 10(18.2%) and 18samples (22.5%) respectively. Statistical analysis showed highly significant difference between mastitis and lactation number.
The results in this work showed that 9 (9.47%), 13 (14.4%), 32 (35.56%), 18 (25.71%) and 33 (60%) were recorded as numbers, of mastitic cows aged 3,4, 5, 6 and 7 years old respectively. Statistical analysis showed highly significant difference between mastitis and age of animal.
Left hind quarters was the highly susceptible quarter in which 35 samples (46.67%), followed by all quarters in which 27 samples (28.42%), right hind quarters 19 samples (22.35%), and finally left and right fore quarters in 14 (23.33%), 10 (11.76%) were recorded respectively. Statistical analysis showed highly significant difference between mastitis and quarters of animal.
The winter season was the most season at which mastitis occurrence was the highest as 57 samples were collected (54.3%) followed by spring season 27 samples were collected (25.23%). The summer season was the lowest season at which mastitis occurred as only 9 samples were collected (9.5%), and finally autumn season 12 samples collected (12.9%). Statistical analysis showed highly significant difference between mastitis and Season.