Comparison of the effects of tylosin and tilmicosin as a systemic treatment of dry Holstein cows

The aim of the present study was to evaluate the efficacy of macrolides to eliminate intramammary infection (IMI) caused by Staphylococcus aureus (S. aureus) and Streptoccus spp. ۳ weeks before calving time. Eighty Holstein dairy cows with subclinical mastitis pathogens were divided into three groups. Three weeks before expected parturition time, cows in group ۱ received tilmicosin (n = ۲۹), cows in group ۲ received tylosin (n = ۳۰) and cows in group ۳ were left as negative control (n = ۲۱). Milk samples were obtained on ۳ and ۷ days after calving. Randomly amplified polymorphic DNA (RAPD) method was determined for all of the S. aureus isolates that had the same isolates before and after parturition. The total cure rate was ۶۳.۳۳, ۷۵.۸۶ and ۶۶.۶۶% for tylosin, tilmicosin and control groups, respectively. Furthermore, cure rates were not significant, when each type of mastitis causing pathogens were considered separately. The incidence of clinical mastitis during ۶۰ days after calving for tylosin, tilmicosin and Control groups was ۲۳.۳۳, ۲۷.۵۸ and ۳۸.۰۹%, respectively. Only four S. aureus isolated before drying-off were similar to post-calving isolate, according to RAPD-PCR method. In conclusion, antibiotic therapy before calving improved the cure rate numerically, however, it was not significant.

کلیدواژه ها:

Dry cow therapy ، Macrolides ، Mastitis ، Staphylococcus aureus ، Tilmicosin