Evaluation of antibiotic residues in milk samples from cows after dry cow therapy

The present study aimed to assess antibiotic residues in milk from animals treated in the pre-term period. A total of 47 animals from dairy farms in Rondônia, Brazil, were used for treatment with commercially available antibiotics especific to the dry period (cloxacillinbenzathine and spiramycin associated to neomycin) and during the lactation period (ceftiofur hydrochloride) at 60 and 30 days after delivery, respectively, in a single application. The detection of antimicrobial residues was performed using the commercial microbiologic kit Eclipse 50 (ZEU-Inmunotec®, Zaragoza). The results showed antibiotic residues in 3.44% of animals treated with cloxacillinbenzathine, in 12.50% of animals treated with spiramycin/neomycin, and in 10% of animals treated with ceftiofur hydrochloride. The period indicated for milk consumption after therapy was 30 days for lactation antibiotic products and 60 days for dry cow therapy. The occurrence of the antibiotic residues in milk is a risk to public health and for the contamination of milk products.