Study on the contagious and envirinmental bovine mastitis with special emphasis to subclinical form

Mastitis is the most prevalent and expensive disease on a dairy farms. Therefore, the aim of this work is to determine the prevalence of clinical and subclinical bovine mastitis in dairy farms with different hygienic measures; study the impact of the riskfactors on the prevalence of mastitis; diagnosis of clinical and subclinical mastitis through traditional tests ,conventional bacterial culture and PCR assays, and to perform trials of treatment for some cases of subclinically mastitic cows during lactatiIn the present work a total of 770 lactating cows from different localities in 3 provinces in Egypt were examined; during the period extended from July 2011 until August 2012. Out of them 710 cows were picked out from three varied dairy farms in additionto 60 individual cases of dairy cows admitted by holders to Clinicof Faculty of Veterinary Medicine, Zagazig University.Concerning to prevalence rate of clinical and subclinical mastitis , it was found that the overall prevalence of mastitis in this study was (37.8%) on cows level, 86 (1l.2%) were clinical and 205 (26.6%) were subclinical cases.In respect to quarter involvement, the affection in two and four quarters is higher than the other quarters affection in clinically and subclinically mastitic cows with prevalence of 24.4% and 44.2% in a clinical mastitis and 34.l % and 43.9% in subclinicwhile in subclinical mastitis one quarter affection is 8.3% and three