Microbiological profile and antibiotics residue in milk of dairy cows with clinical and subclinical mastitis under treatment

Abstract

Mastitis is an inflammatory process of the mammary gland, usually it has an infectious origin which causes economic losses to dairy farming. The use of antimicrobial prophylaxis or treatment of this disease can cause bacterial resistance, favoring infection by opportunistic agents and can also lead to the occurrence of residues in milk. Antimicrobial residues in milk are considered undesirable because they may cause risk for human health and damage to the industries. This project aims to evaluate the general microbiological profile curve and elimination of antibiotic residues in milk from cows with subclinical mastitis and subjected to treatment. It will be evaluated 50 lactating cows Holstein with clinical mastitis and subclinical mastitis. The animals will be treated with intramammary antibiotics of the group of aminoglycosides (gentamicin) for 3 days. Milk samples will be collected for microbiological evaluation prior to initiation of treatment and 12 days after the last day of treatment. Miçk samples are plated on blood agar, agar MacConkey and Sabouraud with chloramphenicol. Samples of milk from mammary quarters, collector balloon and expansion tank will be collected for 11 days after the application of the antibiotic for evaluation of the antibiotic residues. Analysis of trace residues of antibiotics in milk will be carried out using the commercial microbiological inhibition tests MINI Delvotest ® SP-NT and enzyme immunoassay using polyclonal antibodies. The statistical analysis is performed using the chi-square test to compare the percentage values when "n" is greater than five and Fisher's exact test when n is equal to or less than five. Statistical significance is defined by a value of "P" less than or equal to 0.05. (AU)