Efficacy assessment of an intramammary treatment with a new recrystallized enrofloxacin vs ceftiofur and parenteral enrofloxacin in dairy cows with nonsevere clinical mastitis.

A recrystallized form of enrofloxacin as dehydrate-HCl (enro-C) was assessed for bacteriological and clinical cure efficacies in Holstein-Friesian cows affected of nonsevere clinical mastitis. Treatments were enro-Csusp (n = 81), treated with a pharmaceutical suspension of enro-C/quarter; group enro-Cpd (n = 80) treated as above, but using enro-C powder suspended in water; group CF (n = 65), treated with ceftiofur HCl/quarter; and group enroR (n = 66), treated with standard enrofloxacin solution (5 mg/kg, intramuscular). Cows had a mean milk production of 31 L/day and were 2-3 lactational periods old. Treatments were administered every 24 hr for 3 days. Groups treated with enro-C exhibited statistically significant (p > .05) better clinical cure as compared to groups treated with CF or enroR (95.06%, 96.25%, 67.79%, and 57.55%, for enro-Csusp , enro-Cpd , CF, and enroR , respectively). In contrast, probability of bacteriological cure was not statistically different among treatments. Yet, the outstanding clinical and bacteriological cure rates obtained for enro-C for nonsevere cases of mastitis is superior to previously reported data for parenteral enrofloxacin and other antibacterial-intramammary treatments. Impact of using enro-C on the rate and pattern of bacterial resistance, somatic cell counts and milk electric conductivity, must be studied. Also, the use of enro-C for complicated cases of mastitis should be studied and milk withdrawal times must be accurately established.