Impact of bovine subclinical mastitis and effect of lactational treatment

摘要: This thesis aimed to quantify the impact of subclinical mastitis in dairy cattle Netherlands and explore epidemiologic economic effects antimicrobial treatment recently acquired during lactation. First, occurrence (sub)clinical was estimated a one-year observational study. It concluded that herds varied substantially their occurrence, indicating room for improvement udder health. The relation between (indicated by somatic cell count (SCC) ?200,000 cells/ml) clinical investigated next. Primiparae with high composite SCC had fourfold higher risk develop than primiparae low SCC. twofold multiparae. Approximately 25% cases can be prevented when cows are or removed from population. therapeutic lactation were studied randomized field trial 40 Dutch herds. Cows streptococci staphylococci randomly assigned treatment. Treated quarters bacteriological cure decrease control quarters. Evaluating effect duration infection revealed early Staph. aureus tended more effective later isolates obtained genotyped determine whether strains commonly found multiple host species differed primarily associated bovine mastitis. Bacteriological around 2.5 times compared Host adaptation known predictors cure. often penicillin-resistant. Additionally, penicillin-resistant, other strains. direct indirect lactational caused contagious pathogens using dynamic stochastic bio-economic model. Lactational resulted less flare-ups, transmission within herd lower annual costs intramammary infections. must accompanied management measures economically beneficial. Antimicrobial environmental did not seem A decision tree developed select most likely benefit antimicrobials.