PRRS Protection in Commingled Pig Flows
If there is strength in numbers, a field study conducted by Boehringer Ingelheim Vetmedica, Inc. (BIVI), should leave little doubt as to the impact of Ingelvac PRRS ATP vaccine on nursery pigs.
A large commercial system using three-site production with mixed-status breeding herds participated in the study. Weaned pigs were sourced to nurseries based on PRRS status of the sow herds.
Pigs from PRRS-positive (stable and unstable) flow went to positive nurseries. Pigs from negative flow went to separate PRRS-negative nurseries.
PRRS seroconversion predictably occurred in the mid-late nursery phase in the positive nurseries, along with PRRS-associated disease and reductions in performance.
Performance at the negative/naïve nurseries was acceptable and met production targets.
The vaccination program was implemented in February/March of 2005. Pigs entering the positive nursery sites were vaccinated with a 2 ml dose of Ingelvac PRRS. Pigs at the negative sites were not vaccinated. Each group involved more than 300,000 pigs.
Performance of PRRS-vaccinated/PRRS-positive nursery sites was compared to pre-PRRS vaccination performance and to performance of the PRRS-negative nurseries through 2005.
Reid Philips, DVM, technical manager for respiratory biologics for BIVI, reported the study results during the 2006 Allen D. Leman Swine Conference.
Most noteworthy was the impact on mortality rate. Historical data pre-vaccination shows mortality at more than 9 percent for positive nurseries. After PRRS vaccination, the rate dropped to less than 3 percent in the positive nurseries.
Vaccinated pigs from positive sites also performed as well as pigs from the negative sites (see performance table at left).
According to Philips, the take-home message from this trial is that timely vaccination prior to field virus exposure can dramatically reduce mortality and improve performance in nursery pigs.
A year later, all pigs are being immunized for PRRS and commingled, and performance continues at target levels.
As a side note, The National Pork Board estimates that PRRS infections add $5.60 – $7.60 per pig sold to the cost of production.1
1. Neumann, E., et. al., JAVMA, 2005.