M. Iqbal, M. Ali Khan, B. Daraz and U. Siddique¹

Veterinary Research Institute NWFP, Peshawar,
¹Agricultural Training Institute, Peshawar, Pakistan

    Mastitis is one of the most costly diseases of lactating animals.  Bacteria constitute the common etiological agents of mastitis.  In the present study, bacteria associated with mastitis were investigated and their susceptibility to various antibiotics was tested.  Milk samples collected from different sources were subjected to different screening tests (White Side Test, Surf Test and California Mastitis Test). The samples found positive were cultured on tryptose agar, MacConkey’s agar, as well as blood agar, for bacterial isolation. The organism so isolated were identified and subjected to 12 commonly used antibiotics for determination of antibiogram. During the period of 52 months (July, 1997 to October, 2001), 6522 milk samples from cattle, buffaloes, sheep and goats were tested for mastitis, out of which 1512(23.18%) were found positive. Growth of different bacteria was yielded by 236(15.16%) out of the positive ones. Gentamicin, enrofloxacin, norfloxacin and kanamycin were found most effective drugs amongst the 12 antibiotics  tested in vitro.