Comparative studies on clinical and subclinical mastitis in dairy cattle / Samah Elsayed Mahmoud Elsaman ; Supervised Samia Abdelhamid Ahmed , Adel Abdelazim Fayed , Soliman Mohammed Soliman

Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Internal Medicine Infectious Diseases

Bovine mastitis is a significant economic threat for the dairy sector of animal production worldwide including Egypt and is one of the multifactorial diseases in dairy farms, which has many risk factors that provoke the disease.The objectives of this study are, assess the effects of births, season, and lactation on the occurrence of clinical and subclinical mastitis, also the identification of the most common bovine intramammary infection-causing bacterial pathogens through isolation and molecular detection. A total of 295 pathogens of 6 different species were isolated from udder in dairy farms in five different governorates. The pathogens founded in this study were Escherichia coli contributed for (41.3%)of all cultured pathogens followed by Staphylococcus aureus (25.8%), Streptococcus agalactiae (0.7%), Streptococcus dysgalactiae (16.9%), other staphylococci (5.4%)and other non-identified isolates (9.8%).The antibiotic resistance patterns were determined for 11 antibiotic drugs using the disc diffusion method following Clinical and Laboratory Standards Institute recommendations, the minimum inhibition concentration (MIC) using ofloxacine, cefquinome, tetracycline and amoxicillin clavulanate drugs and the molecular detection of udder pathogens and their virulence genes as rfbEO157 encoding gene as Shiga toxin-producing E. coli (STEC), coagulase gene andmethicillin-resistance encoding gene (MecA)

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