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Table 3 Multivariable multi-level Poisson regression using pneumonic lung condemnation rates

From: Suitability of bovine portion condemnations at provincially-inspected abattoirs in Ontario Canada for food animal syndromic surveillance

Variable

Categories

IRR1

Std. Err.

P-value

 

95% CI

Year

2001

 

2002

0.83

0.02

< 0.01

0.79

0.86

 

2003

1.14

0.02

< 0.01

1.09

1.19

 

2004

0.80

0.03

< 0.01

0.76

0.84

 

2005

0.75

0.03

< 0.01

0.71

0.79

 

2006

0.45

0.03

< 0.01

0.43

0.49

 

2007

0.31

0.04

< 0.01

0.28

0.34

Animal class

Calves

 

Cows

0.30

0.23

< 0.01

0.19

0.47

 

Heifers

0.39

0.11

< 0.01

0.32

0.49

 

Steers

0.16

0.07

< 0.01

0.14

0.19

Season

Winter

 

Spring

1.07

0.02

< 0.01

1.03

1.11

 

Summer

0.96

0.02

0.03

0.93

0.99

 

Fall

1.10

0.02

< 0.01

1.06

1.15

Region

Central

 

Eastern

1.88

0.54

0.24

0.66

5.39

 

Northern

0.02

1.31

< 0.01

0.001

0.20

 

Southern

0.75

0.47

0.54

0.30

1.90

 

Western

0.98

0.46

0.97

0.40

2.42

Rating

C

 

AAA

0.24

1.26

0.26

0.02

2.85

 

AA

0.18

0.64

0.01

0.05

0.62

 

A

0.11

0.63

< 0.01

0.03

0.37

 

B

0.15

0.63

< 0.01

0.04

0.50

 

unrated

0.29

0.64

0.048

0.08

0.99

# of animals

1–286

 

287–498

0.70

0.12

< 0.01

0.56

0.89

 

499–841

0.36

0.15

< 0.01

0.27

0.48

 

842–27286

0.27

0.14

< 0.01

0.20

0.35

# of weeks

1–43

 

44–49

1.72

0.07

< 0.01

1.50

1.97

 

50–51

2.84

0.06

< 0.01

2.55

3.16

 

52

2.31

0.05

< 0.01

2.11

22.54

Season x animal class

Winter x calves

 

Spring x heifers

0.93

0.05

0.14

0.85

1.02

 

Summer x heifers

0.92

0.05

0.10

0.83

1.02

 

Fall x heifers

0.83

0.05

< 0.01

0.76

0.92

 

Spring x steers

0.91

0.04

0.01

0.84

0.98

 

Summer x steers

0.94

0.04

0.10

0.88

1.01

 

Fall x steers

0.82

0.04

< 0.01

0.77

0.88

 

Spring x cows

0.78

0.09

0.01

0.66

0.93

 

Summer x cows

0.73

0.09

< 0.01

0.61

0.88

 

Fall x cows

0.65

0.09

< 0.01

0.55

0.78

Region x animal class

Central x calves

 

South x heifers

0.37

0.09

< 0.01

0.31

0.45

 

West x heifers

0.65

0.09

< 0.01

0.53

0.78

 

North x heifers

6.58

1.25

0.13

0.56

76.70

 

East x heifers

0.72

0.16

0.05

0.54

0.99

 

South x steers

0.68

0.07

< 0.01

0.60

0.78

 

West x steers

2.81

0.06

< 0.01

2.52

3.14

 

North x steers

67.90

1.06

< 0.01

8.44

546.45

 

East x steers

1.64

0.14

< 0.01

1.25

2.15

 

South x cows

0.26

0.27

< 0.01

0.15

0.45

 

West x cows

1.60

0.20

0.02

1.09

2.34

 

North x cows

7.39

1.49

0.18

0.40

136.25

 

East x cows

1.05

0.24

0.85

0.66

1.66

Year x animal class

2001 x calves

 

2002 x heifers

1.84

0.08

< 0.01

1.59

2.13

 

2003 x heifers

1.53

0.08

< 0.01

1.32

1.78

 

2004 x heifers

1.64

0.08

< 0.01

1.41

1.92

 

2005 x heifers

1.24

0.08

< 0.01

1.06

1.45

 

2006 x heifers

2.23

0.08

< 0.01

1.90

2.63

 

2007 x heifers

2.68

0.09

< 0.01

2.25

3.20

 

2002 x steers

2.05

0.05

< 0.01

1.85

2.27

 

2003 x steers

2.27

0.05

< 0.01

2.06

2.49

 

2004 x steers

2.44

0.05

< 0.01

2.20

2.69

 

2005 x steers

1.64

0.05

< 0.01

1.48

1.83

 

2006 x steers

2.60

0.06

< 0.01

2.32

2.92

 

2007 x steers

2.86

0.06

< 0.01

2.54

3.23

 

2002 x cows

1.07

0.19

0.74

0.73

1.55

 

2003 x cows

3.09

0.14

< 0.01

2.35

4.08

 

2004 x cows

3.63

0.14

< 0.01

2.76

4.77

 

2005 x cows

1.57

0.15

< 0.01

1.17

2.12

 

2006 x cows

2.57

0.16

< 0.01

1.89

3.49

 

2007 x cows

2.08

0.18

< 0.01

1.46

2.98

  1. 1Incidence rate ratio.
  2. Multivariable multi-level Poisson regression model (PQL-2) investigating the association between pneumonic lung condemnation rates in Ontario provincial abattoirs and year-animal class interaction, season-animal class interaction, region-animal class interaction, number of animals, number of weeks of processing and audit rating.