Isolation and identification of some bacteria causing subclinical mastitis in cows

Isolation and identification of different type of bacteria from milk samples of 20 clinically healthy cow from different area in Mosul city between the period from May 2007 to May 2008 was carried out. The quality of the milk was screened using white side test. Identification of the isolate was carried out depend on the morphology of colony and biochemical test. The results indicated that total percentage of the infectivity of milk was (80%). The coagulase negative Staphyloccoci (CNS) was dominant. The more frequent from them was Staphylococcus sciuri which was (21.8%) followed by Staphylococcus aureus (18.7%), Streptococcus spp. (15.6%) then G-ve Coccobacill, Arcanobacterium pyogenes (9.3%) and Micoccocus (3.1%). Staphylococcus sciuri and CNS were more sensitive to Chloramphenicol and Ciprofloxacin but resistance to Ampicillin and Penicillin G.