The Effect Of Intra mammary Infusion of Tilmicosin As A Dry Cow Therapy On The Rate of Sub - clinical Mastitis

In order to evaluate tilmicosin efficacy in dairy cows to reduce the rate of intra mammary infections in dry period and new infections in post partum period, sixty quarters of 30 Holstein cows in the dairy farms of Fashapoye in Tehran suburb infected by gram positive bacteria were divided equally in two , test and control groups .Bacterial examination and somatic cell count were examined at the first day of drying ,and then , the animals of test group were infused by tilmicosin(5 ml, intra mammary 30% ,Razak,Tehran,Iran ) and control group by Cloxacillin (10 ml ,500 mg, Cloxalmo, DC oint; zistkimia. CO.Tehran. Iran.).Bacterial examination at 7 days and somatic cell count at 10 days after parturition were examined repeatedly .The rates of intra mammary infections and new infection rates were compared by chi esquire and student T test in two groups .Results showed that tilmicosin has less effect on reduction of intra mammary infection due to Chorine bacterium bovis and has no effect on streptococcus agallactiae but has the same effect as Cloxacillin against coagulase negative staphylococci and has more effect against staphylococcus aureus (p<0.01) . Tilmicosin were more effective than cloxacilline against new infections. In conclusion, tilmicosin might be an acceptable antibiotic to dry cow therapy, but more information is needed before recommendation.