TABLE 1

Clinical, virological, and pathological results for vaccinated and control animals on the 3 farmsa

ParameterInterval or age (wks)Vaccinated animalsControl animals
Farm AFarm BFarm CFarm AFarm BFarm C
ADWG (g/pig/day)3–10401 ± 51416 ± 58454 ± 58393 ± 37418 ± 39446 ± 38
10–16638 ± 82*648 ± 62*708 ± 54*592 ± 39606 ± 56670 ± 51
16-S797 ± 43*841 ± 72*878 ± 71*758 ± 75795 ± 69817 ± 67
3-S630 ± 21*647 ± 26*691 ± 27*605 ± 32626 ± 23656 ± 23
Market wt (kg)103.548102.3108.2*103.625103.588103.125
Days to market181174173188179177
Mortality rate (no. dead/total)0/251/250/254/203/204/20
No. of viremic pigs/total30/250/250/250/200/200/20
619/2518/2518/2517/2015/2014/20
108/2519/2411/257/1913/198/20
160/255/246/250/176/182/18
No. of nasal shedders/total30/250/250/250/200/200/20
614/2516/2512/2513/2011/2011/20
109/2513/247/258/1912/198/20
160/250/240/250/170/180/18
Macroscopic lung lesion score169 ± 8.415.2 ± 2.15 ± 5.118.8 ± 3.824 ± 6.612.4 ± 2.9
S4.2 ± 2.96 ± 4.22.2 ± 2.65 ± 3.811.5 ± 74.1 ± 4.1
Microscopic lung lesion score160.4 ± 0.50.6 ± 0.70.5 ± 0.91.3 ± 1.11.3 ± 0.90.8 ± 0.7
S0.2 ± 0.30.4 ± 0.30.2 ± 0.20.3 ± 0.40.8 ± 0.50.3 ± 0.3
PRRSV antigen score1.7 ± 1.41.4 ± 1.31.1 ± 1.42.4 ± 1.91.6 ± 1.61.2 ± 1.6
  • a S, date of shipment to slaughter. *, significantly higher value for vaccinated animals than control animals (P < 0.05); †, significantly lower value for vaccinated animals than control animals (P < 0.05).