CategoryAnimal Science - Swine Nutrition
Date Full Report Received04/23/2014
Date Abstract Report Received04/23/2014
Funded ByNational Pork Board
This research examined the impact PRRSV infection had on grow-finisher gilt performance, apparent total tract digestibility and tissue accretion rates. Thirty littermate pairs of Choice Genetic maternal line gilts were split between two modified commercial swine finisher barns at six pigs per pen, five pens per barn. Each pen was scaled to represent industry standard square footage per pigs and feeder space. One barn (CHAL; n=30 pigs) was challenged with a live field strain of PRRS isolated from north-central Iowa and the other barn was designated a PRRS naïve control barn (CONT, n=30 pigs). Growth rates, feed intake and feed efficiency were then assessed from 70 – 285 lbs body weight. Whole body composition was assessed at -1, 42 and 80 days post inoculation (dpi) by Dual X-ray Absorptiometry (DXA). Apparent total tract digestibility of dry matter, nitrogen and energy was assessed at 21 and 70 dpi. Blood viremia, metabolites and inflammation markers were also assessed. Results from this study showed that PRRSV infection reduced ADG, ADFI and feed efficiency by 6-10%. This was most severe in the first 28 dpi in which these performance measures were reduced by 30-50% compared to the CONT gilts. PRRSV infection also reduced ATTD of dry matter, energy and nitrogen by 3-5% at 21 dpi and these were stilled attenuated at dpi 70. To get the PRRSV CHAL pigs to the same live weight (~285 lbs), this treatment group remained on test for an extra 14 days. The CHAL pigs also had attenuated whole body lean, protein and fat tissue accretion rates compared to their CONT counterparts. Tissue accretion was mostly impacted during the first six weeks of the study. At market weight, CHAL pigs had leaner carcasses and reduced yield percentage compared to the CONT gilts. Altogether, these data clearly demonstrate that PRRSV infection reduces digestibility, feed efficiency and protein accretion rates in grow-finisher pigs. Furthermore, our conservative economic analysis indicated that PRRSV infection alone, without mortality, would cost producers $6-$13 per pig.