IU/mL for the duration of the study (2–3 y). There was no significant difference in the response to vac- cination or duration of RVNA levels 0.5 IU/mL between horses 20 and horses 20 years old. RVNA levels 0.5 IU/mL persisted for 1 year in only one of the seven naïve horses.
4. Discussion
A rabies revaccination interval of more than 1 year may be appropriate in previously vaccinated horses, but not in naïve horses.
Acknowledgments
This study was supported by the Bernice Barbour Foundation and the Center for Equine Health, Uni-
versity of California, Davis, with funds from the Oak Tree Racing Association, the state of California pari- mutuel wagering fund, and contributions from pri- vate donors. Vaccine was kindly supplied by Merial, Inc. The T. S. and K. D. Glide Foundation, Davis, CA are acknowledged for their help in pro- viding horses for this study.
Declaration of Ethics
The Authors have adhered to the Principles of the Veterinary Medical Ethics of the AVMA.
Conflict of Interest Rabies vaccine was supplied by Merial Inc., Duluth, GA 30096.
