Treatment of non-severe mastitis in Brazilian dairy cows: a comparative study between amoxicillin-clavulanic acid and a conventional protocol

Abstract

The association of amoxicillin and clavulanic acid has shown high efficacy to treat mastitis worldwide, also promoting a shorter milk disposal period compared to other antimicrobials. However, no previous investigations regarding its application to treat mastitis in Brazilian dairy cows were developed. This study evaluated the effectiveness of amoxicillin-clavulanic acid to treat Brazilian dairy cows with mastitis, comparing it with a reference protocol treatment combination of tetracycline, neomycin and bacitracin. Holstein cows (n = 468) from three different dairy herds in Brazil were assigned to two groups: combination of tetracycline, neomycin and bacitracin (n = 178; positive control group) and amoxicillin-clavulanic acid protocol (n = 290). Before the treatment, milk samples were collected and cultivated in chromogenic media. After finishing the antimicrobial treatment (intramammary), milk samples were also collected and cultivated in chromogenic media. Results from microbiological analysis obtained before and after treatment were compared to determine the healing rate. Nine different microbiological agents were identified: eight of environmental origin and one of contagious origin; being eight gram-positive and one gram-negative bacteria. TThe positive control group and the treatment group showed similar healing rate (86.5% and 90.3%, respectively; P > 0.05). No differences were found between the groups for the healing rate, when the causing agent was considered. Therefore, it is possible to indicate the amoxicillin-clavulanic acid-based protocol to treat intramammary mastitis in Brazilian dairy cows, achieving great healing rates and providing a substantial reduction in milk disposal.