No Effect of PRRS Vaccination Found in Finisher Performance

Sirrah-Bios PRRSV-RS vaccine administered at four days of age did not affect performance or mortality in a commercial finisher herd, reported M.L. Potter at the Kansas Swine Day 2009.

2 March 2010

3 minute read

M.L. Potter explained that a total of 1,561 pigs (initially four days of age) were used to determine the effects of a porcine reproductive and respiratory syndrome virus (PRRSv) subunit vaccine, PRRSV-RS (Sirrah-Bios, Ames, Iowa), on mortality rate and finisher pig growth performance in a PRRSv-positive commercial herd.

Pigs were randomly assigned by litter to either the subunit PRRSv vaccine or non-vaccinated control group. Pigs in the vaccinated group received an intramuscular injection of 1 mL PRRSV-RS vaccine at processing (approximately four days after birth) and again at weaning (approximately 24 days of age).

Vaccinated and control pigs were comingled in a single nursery during the nursery phase. In the finishing phase, pigs were housed in a standard commercial curtain-sided finisher barn by treatment and gender by pen, with treatments randomly distributed across pens.

Mortality was tracked from processing (four days of age) to market (days 187 to 193). There were no differences between the control and vaccinated pigs for cumulative mortality (21.5 versus 20.6 per cent, P=0.67) or for mortality during each production phase (processing to weaning: 9.5 versus 7.1 per cent, P=0.08; nursery: 9.3 versus 9.2 per cent, P=0.95; finishing: 4.4 versus 5.9 per cent, P=0.20).

Pigs were initially weighed by single-sex pens (control or vaccinated) two weeks after placement into the finisher (day 0), and at that time, control and vaccinated mean pig weights were not different (58.4 versus 58.7 lb, P=0.90).

Pens of pigs were subsequently weighed every two weeks, and feed consumption was recorded to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed to gain (F/G).

Overall (days 0 to 112), control and vaccinated pig performance was similar (ADG: 1.96 versus 1.93 lb, P=0.45; ADFI: 5.35 versus 5.36 lb, P=0.94; F/G: 2.74 versus 2.78, P=0.15) throughout the finishing period. This resulted in no difference (P=0.79) in off-test (day 112) weights between control (271.9 lb) and vaccinated (270.4 lb) pigs.

Potter and colleagues concluded that this sub-unit PRRSv vaccine did not affect finisher pig performance or mortality in this commercial herd.

Reference

Potter M.L., S.S. Dritz, S.C. Henry, L.M. Tokach, J M. DeRouchey, M.D. Tokach, R.D. Goodband and J.L. Nelssen. 2009. Effects of Sirrah-Bios PRRSV-RS vaccine on mortality rate and finisher pig performance. Proceedings of the Kansas Swine Day 2009, 33-37.