Use of antimicrobials in the treatment of reproductive diseases in cattle and horses.

Use of antimicrobials for veterinary indications related to reproduction in cattle and horses is reviewed. Antimicrobial compounds are widely used to treat and prevent infections of reproductive organs. Total amounts of antimicrobials for such purposes, estimated by weight, are low compared with major uses in food animals. The most common reproduction-related indication in cattle is mastitis. The number of intramammary products available for treatment of mastitis in the European Union is high. Metritis and endometritis also require antimicrobial treatment of cattle and specific products for intrauterine administration are available. The traditions and practices associated with the use of these products vary considerably among different countries. Parenteral antimicrobial treatment is used to treat acute clinical mastitis and puerperal metritis. Pharmacological characteristics of the antimicrobial administered parenterally are critical to achieve and maintain therapeutic concentrations in the target organs. In mares, the most common indications associated with reproduction are endometritis, retained placenta and placentitis. The number of authorized antimicrobial products for horses is limited. Horses are treated individually and off-label use of antimicrobials is very common. In veterinary indications related to reproduction, treatment practices exist that cannot be considered to be evidence-based or responsible use of antimicrobials. Not all products for local treatment have proven efficacy data. Examples of unnecessary uses are routine treatment of cows with retained placenta and use of post-breeding antibiotic treatments in mares.