2015 ACVIM Forum Research Abstract Program

These findings suggest that beginning the initial series of vaccinations in foals 4 months of age is a viable option although foals with the higher level of WNV maternal antibodies may require 2 doses before a response is observed. These findings also suggest that waiting to vaccinate until WNV maternal antibodies have disappeared may not be required. Currently, 6.6 mg/kg q24 hour gentamicin and 21 mg/kg q24 hour amikacin, respectively, are commonly used to treat infections in horses and foals. Doses of 7-9 mg/kg gentamicin and 25 mg/kg amikacin have been suggested to reach adequate peak concentrations of 8-109 minimum inhibitory concentration (MIC), although these doses have not been critically evaluated in clinical studies. The objective of this study was to measure peak and trough plasma concentrations in horses treated with 9 mg/kg gentamicin q24 hour IV and in foals treated with 25 mg/kg of amikacin q24 hour IV and to compare the peak concentrations to the MICs of local gram-negative bacteria.