Skip to main content

Table 4 Model 2.

From: Porcine reproductive and respiratory syndrome virus (PRRSV) in GB pig herds: farm characteristics associated with heterogeneity in seroprevalence

Variable n Coefficient SE p CIa   OR CIb  
Intercept   2.48 0.25       
Age category
8 weeks   reference      reference   
14 weeks 16 -0.06 0.2 0.76 -0.45 0.33 reference   
Gilts 16 0.52 0.2 0.01 0.12 0.92 reference   
Parity 1 16 0.93 0.2 < 0.01 0.53 1.33 10.8 3.54 33.02
Parity 2 16 1.14 0.21 < 0.01 0.74 1.54 16.3 5.44 48.84
Parity 3 16 1.19 0.2 < 0.01 0.79 1.59 18.8 6.4 54.88
Parity 4 16 1.08 0.2 < 0.01 0.68 1.48 12.72 4.21 38.41
Parity 5+ 16 1.31 0.2 < 0.01 0.91 1.71 8.39 2.87 24.56
Distance to nearest pig unit (miles) 16 -0.06 0.02 < 0.01 -0.1 -0.01 0.88 0.78 0.99
Quarantine facilities on farm
Not present 4 reference        
Present 12 -0.56 0.24 < 0.05 -1.02 -0.1 0.27 0.08 0.87
Estimation of random effects:
Variation between herds   0.12 0.06       
Variation between pens   0.29 0.05       
Variation between pigs   0.24 0.01       
  1. Multivariable three level mixed model of factors associated with log IRPC of 774 pigs belonging to 16 herds that had seronegative young stock.
  2. Sample size (n); standard error (SE); probability function (p); 95% confidence interval (CIa) when pigs' log IRPC (+12) values were used as a continuous outcome variable; Odds Ratios (OR) and 95% confidence interval (CIb) when pig-level seropositivity (absence/presence of antibodies) was used as a comparative binary outcome variable (exp(coefficient+/-(1.96 × standard error))).