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Table 6 Multivariable negative binomial model using a GEE1 approach

From: Factors associated with whole carcass condemnation rates in provincially-inspected abattoirs in Ontario 2001-2007: implications for food animal syndromic surveillance

Covariate IRR2 Robust Standard Error P-value 95% CI
Animal class     
Calves --- --- --- ---
Cows 6.73 2.40 < 0.001 3.35 - 13.52
Heifers 0.47 0.10 < 0.001 0.31 - 0.72
Steers 0.46 0.12 0.01 0.29 - 0.74
Year     
2001 --- --- --- ---
2002 1.37 0.21 0.04 1.02 - 1.84
2003 0.70 0.16 0.11 0.45 - 1.09
2004 0.56 0.13 0.02 0.36 - 0.90
2005 0.93 0.20 0.74 0.61 - 1.43
2006 1.05 0.23 0.80 0.69 - 1.63
2007 1.16 0.29 0.56 0.71 - 1.88
Season     
Winter --- --- --- ---
Spring 0.88 0.07 0.07 0.76 - 1.01
Summer 0.82 0.06 0.01 0.71 - 0.95
Fall 0.77 0.05 < 0.001 0.69 - 0.87
Audit rating     
C --- --- --- ---
AAA 0.32 0.30 0.22 0.05 - 2.01
AA 0.43 0.12 0.01 0.25 - 0.74
A 0.64 0.11 0.01 0.46 - 0.89
B 0.56 0.11 0.01 0.39 - 0.82
unrated 1.41 0.35 0.17 0.87 - 2.31
Price     
Below median --- --- --- ---
Above median 1.12 0.05 0.02 1.02 - 1.23
Year x animal class     
Calves and 2001 --- --- --- ---
Cows and 2002 0.61 0.12 0.01 0.42 - 0.88
Cows and 2003 1.13 0.34 0.69 0.63 - 2.05
Cows and 2004 0.83 0.30 0.61 0.40 - 1.72
Cows and 2005 0.48 0.14 0.01 0.27 - 0.86
Cows and 2006 0.45 0.12 0.01 0.27 - 0.78
Cows and 2007 0.51 0.19 0.06 0.25 - 1.04
Heifers and 2002 0.61 0.14 0.03 0.39 - 0.95
Heifers and 2003 1.46 0.44 0.21 0.81 - 2.65
Heifers and 2004 1.05 0.30 0.85 0.61 - 1.83
Heifers and 2005 0.88 0.24 0.63 0.51 - 1.50
Heifers and 2006 0.93 0.22 0.77 0.59 - 1.48
Heifers and 2007 0.71 0.23 0.29 0.39 - 1.33
Steers and 2002 0.74 0.14 0.12 0.51 - 1.08
Steers and 2003 1.40 0.43 0.28 0.77 - 2.54
Steers and 2004 1.63 0.50 0.11 0.89 - 2.99
Steers and 2005 1.02 0.28 0.94 0.60 - 1.73
Steers and 2006 1.42 0.44 0.26 0.78 - 2.61
Steers and 2007 0.90 0.32 0.77 0.45 - 1.81
Correlation value = 0.067
  1. 1 Generalized estimating equation using an exchangeable correlation structure to account for repeated measurements among provincial abattoirs
  2. 2 Incidence rate ratio
  3. Multivariable negative binomial models using a GEE1 approach investigating the association between condemnation rates in Ontario provincial abattoirs and animal class, year, season, price, year-animal class interaction and audit rating based on the multivariable GEE model.