The determination of subclinical mastitis incidence in dairy cows in Bolu Mudurnu region

The present study was performed to investigate the subclinic mastitis incidence and to detect the factors effected on California Mastitis Test (CMT) scores and bacteriology results in different dairy farms at Mudurnu district of Bolu province, Turkey.CMT was performed on totally 774 udders of 195 Hosltein Fresian, Swiss Brown and Simmental dairy cows in 32 farms and at least one CMT positive 125 udders of 100 cows were included to the study. Milk samples were evaluated microbiologically and antibiotic sensitivity test was carried out.The percentage of CMT positive cow rate was 51.28% and 63% of milk samples of these animals showed positive microbiological growth. CMT positive udder percentage found 16.14% in all examinated udders (n:774) and 60.80% of milk samples collected from CMT positive udders showed microbiological growth. In all dairy farms, positive microbiological growth rate was 57.58% of 99 samples in CMT +1 animals, 85% of 20 samples in CMT +2 animals, 66,67% of six samples in CMT +3 animals and positive correlation was observed between CMT scores and microbiology results, however, this was not significant statistically.E. coli, Candida spp., S. uberis, coagulase negative staphylococcus, S. aureus, Proteus spp., and Bacillus spp. were isolated with the percentage of 28.9, 24.21, 19.53, 19.53, 3.9, 2.34 and 1.56%, respectively.According to the farm localization, CMT positive cows did not show significant difference between lactation number/stage and age. Moreover, it was observed that farm localization, age, lactation number/stage, breed and localization of udder did not affect CMT scores and microbiological results. Microbiologically positive samples showed that microorganisms were sensitive against amoxicillin+clavulanic acid and oxytetracycline, whereas resistant against gentamicin, ceftiofur, enrofloxacin and cobactam.In conclusion, it was observed that mastitis was stil a problem and milking system, poor milking hygiene, ineffective mastitis control programs were more important mastitis causing factors than age, lactation number/stage and breed of cows in dairy farms. On the other hand, it is suggested that blind antibiotic theraphy may be an important factor contributing the antibiotic resistance.Key words: Dairy cow, Subclinic mastitis, incidence, antibiotic sensitivity test