Recurrent reproductive failure associated with porcine reproductive and respiratory syndrome in a swine herd.

An investigation of a case of recurrent reproductive failure in a swine herd was conducted. The subject farm (A) and a neighboring farm (B) had experienced an acute outbreak of porcine reproductive and respiratory syndrome in 1990. During 1992, farm A experienced recurrent episodes of conception failure, stillbirths, preweaning mortality, and sow mortality. Similar clinical findings were not evident on farm B. Evaluation of production records indicated that the problem was occurring in first-parity litters. It was learned that replacement gilts for farm A were being purchased from an outside source, whereas farm B raised its own replacement gilts. Indirect fluorescent antibody testing of gilts from both farms indicated a high prevalence of seronegative gilts on farm A vs a high prevalence of seropositive gilts on farm B. Although there is no correlation between indirect fluorescent antibody titers and immunity, it would appear that exposure to porcine reproductive and respiratory syndrome virus prior to breeding is essential to prevent reproductive disease.