Rabies Vaccination for Sheep and Goats: Influence of Booster on Persistence of Antibody Response.

Infrequent rabies cases occur in Israel, endangering humans and animals. While dogs receive mandatory vaccinations, farm animals are vaccinated voluntarily. However, optimal vaccination protocol for small ruminants is lacking. The aim of this study was to test the immunological responses to the rabies vaccine, with or without a booster, in sheep and goats; 70 ewes and 49 does participated in the trial. Following the first vaccine, 88% of the ewes and 100% of the does had a sufficient level of rabies antibodies (>0.5 IU/mL) 30 days post-vaccination. A year later, 82% of the ewes that had received a booster dose remained protected, whereas 46% of the non-boosted ewes had a sufficient antibody level. For does, 83% of those receiving a booster maintained sufficient antibody levels 1 year later; 80% of the non-boosted does remained protected, demonstrating no significant contribution of the booster dose in this group of goats. However, while the initial immunological response of the does was higher, the change in response between 1 month and 12 months post-vaccination differed significantly between species, with a greater titer reduction in the does. Differential immunological responses between individuals and between species warrant longer-term studies to recommend a proper vaccine protocol for each species.