February 15, 2018

Interpretive summary: Porcine Reproductive and Respiratory Syndrome Virus Reduces Feed Efficiency, Digestibility, and Lean Tissue Accretion in Grow-finish Pigs

Review: Porcine Reproductive and Respiratory Syndrome virus reduces feed efficiency in grow-finish pigs.

By: Anne Zinn

In a recent study published in the December 2017 issue of Translational Animal Science, a research team at Iowa State University has concluded that Porcine Reproductive & Respiratory Syndrome (PRRS) virus reduces feed efficiency in grow-finish pigs.

Porcine Reproductive & Respiratory Syndrome virus is a major swine virus that causes reproductive impairment in sows, as well as respiratory disease, reduction in growth rates, and mortalities in pigs of all ages. Porcine Reproductive & Respiratory Syndrome virus is estimated to cost the pork industry $664 million annually, primarily from loss of production. While there are numerous reports on the impact of PRRS virus on growth rates and immunity in grow-finish pigs, there is little information on how PRRS disrupts tissue accretion rates, digestibility, and feed efficiency. The objective of this study was to determine the longitudinal impact of PRRS virus on growing-finishing pigs’ digestibility, tissue accretion rates, and feed efficiency, as well as the economic impact of grower pigs infected with PRRS virus.

This study was conducted in central Iowa in the fall of 2012 through the winter of 2013. 60 PRRS-free gilts, split into 2 barns and grouped into 5 pens, were used. All pigs in 1 barn were injected with a live PRRS strain common to Northern Iowa (CHAL), and all pigs in the second barn were given a saline control injection (CONT). Pig performance was assessed until each group reached market body weight (128kg), and longitudinal apparent total tract digestibility and body composition were assessed using Dual-energy x-ray absorptiometry to estimate lean, protein, fat, and bone accretion rates.

Results clearly indicate that PRRS virus significantly reduces feed efficiency and digestibility, as compared to non-infected pigs, and demonstrates a persistent negative impact on growth rate and fees intake in the short- and long-term. In addition, the economic analysis indicated that the economic impact of PRRS virus was estimated to be between $3 and $11 per pig, depending on feeder space. The research team concluded that, as a result of the PRRS virus, growth of the pigs was impacted and resulted in an extra 14 days on feed to achieve the same market body weight as the non-infected pigs. Porcine Reproductive & Respiratory Syndrome virus continues to be one of the most economically important pathogens to the U.S. swine industry, and this research could inspire a deeper evaluation of the virus and how it is treated.

The full title of this paper is, “Porcine Reproductive and Respiratory Syndrome virus reduces feed efficiency, digestibility, and lean tissue accretion in grow-finish pigs,” and can be found here.