Öz
The present study was performed to investigate the effect of some risk factors on subclinical mastitis in dairy cows. California Mastitis Test (CMT) was performed on 774 mammary quarters of 195 Holstein Friesian, Swiss Brown and Simmental cows and at least one CMT positive 125 milk samples of 100 cows were included into the study. Milk samples were evaluated microbiologically and antibiotic sensitivity test was carried out. CMT positive cows rate was 51.28% and 63% of these animals showed positive microbiological growth. CMT positive samples percentage found 16.14% in all mammary quarters (n:774) and 60.80% of milk samples collected from CMT positive mammary quarters showed microbiological growth. E.coli, Candida spp., S.uberis, Coagulase Negative Staphylococcus, S.aureus, Proteus spp., and Bacillus spp. were isolated as 28.9, 24.21, 19.53, 19.53, 3.9, 2.34 and 1.56%, respectively. According to farm localization, CMT positive cows did not show significant difference between lactation number/period and age. Moreover, farm localization, age, lactation number/period, breed and localization of mammary quarters did not affect CMT scores and microbiological results. Microbiologically positive samples showed that microorganisms were sensitive against amoxicillin+clavulanic acid and oxytetracycline, whereas those were resistant against gentamycin, ceftiofur, enrofloxacin and cefquinome. In conclusion, it is thought to be that age, breed, lactation number and lactation period of cows are not effective factors causing subclinical mastitis as much as inadequate hygiene, improper milking system and mastitis control programs. Furthermore, it is strongly suggested that ampiric antibiotic therapy can be an important risk factor for contributing antibiotic resistance.