The effect of PRRSV on reproductive parameters in swine herds

Objective:To compare 1994-1995 reproductive performance of herds free of porcine reproductive and respiratory syndrome virus (PRRSV) to those infected with PRRSV, and to compare those positive herds that reported clinical reproductive signs to positive herds that did not report clinical reproductive signs. Methods: A total of 132 swine producers throughout the midwestern United States agreed to participate in this study by supplying a copy of their PigCHAMP® records and completing an eight-page questionnaire regarding management protocols. One year's data (August 1994-July 1995) were summarized for each herd and the yearly production means compared. Herds were categorized according to their PRRS status, as reported by the producers, and assigned to one of the following categories: PRRSV negative ("neg"), PRRSV negative and vaccinating for PRRSV ("neg-vac"), PRRSV positive without reproductive clinical signs ("pos-subclin"), or PRRSV positive with reproductive signs ("pos-clin"). Results: Overall, the reproductive performance of the pos-clin herds was significantly lower than that of neg herds. Pos-subclin herds had reproductive performance similar to pos-clin herds. Neg and neg-vac herds had similar reproductive performance. Implications: Subclinical PRRS can be as detrimental to the reproductive performance of a herd as clinical PRRS. Vaccinating appears to keep performance at the same levels as are maintained in the negative herds.