Incidence rate of clinical mastitis and antibiotic susceptibility of mastitis-producing pathogens in dairy cattle from Northern Antioquia, Colombia

Abstract

<em>Introduction</em>: Mastitis is defined as the inflammation of the mammary gland causing great economic losses in dairy herds, which merits investigation. <em>Objective</em>: To determine the incidence rate of clinical mastitis IRCM, associated etiology, and antibiotic sensitivity of pathogens isolated from cases of mastitis in dairy cattle. <em>Materials and methods</em>: 37 herds were followed during 12 months for clinical mastitis (CM) diagnosis. Milk samples from CM cases were bacteriologically cultured, which underwent, along with isolates from subclinical mastitis cases from a previous study, antibiotic susceptibility testing. For data analysis, standard descriptive statistics were used. <em>Results</em>: The IRCM was 13.8 cases per 100 cows-year at risk. A total of 188 pathogens of CM cases were isolated, among which <em>Streptococcus agalactiae, Streptococcus pyogenes</em>, and <em>Corynebacterium spp.</em> were the most frequent, with 29.8%, 11.7%, and 5.9%, respectively. A high susceptibility of contagious bacteria was found for cloxacillin and cefoperazone. <em>Conclusions</em>: The present study found an IRCM of 13.8 cases per 100 cows-year at risk. The most prevalent pathogens identified in cases of CM were contagious. A high sensitivity of contagious bacteria was found for most β-lactam antibiotics.