EVALUATION OF THE LONG-TERM IMPACT OF PROACTIVE SEASONAL VACCINATION WITH MODIFIED LIVE PRRS VACCINE ON BREEDING HERD PERFORMANCE IN A LARGE PRODUCTION SYSTEM

摘要

Where PRRS elimination from swine breeding herds is impractical due to the risk and consequent cost of virus reintroduction, practices focused on minimizing controllable virus introduction and circulation risks are often insufficient to achieve desired control of clinical PRRS outbreaks. Under such conditions, achieving and maintaining a high level of population immunity in high-risk breeding herd populations can be beneficial, particularly during periods where there is a high risk of nonresident virus introduction and an increase in virus circulation.