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Table 3 Univariable random effects logit models predicting the probability of an animal disclosing with a visible lesion at slaughter

From: Bovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infection

Variable (outcome = VL)

N-positive (% positive)

 

N

OR (95%CI)

P-value

Risk factors at animal level

     

b-a PPD reaction size

  

5698

 

<0.001

 

18 (11.92%)

<0 mm

 

2.39 (1.19–4.82)

 
 

22 (4.7%)

0 mm

 

Ref.

 
 

211 (25%)

1-4 mm

 

7.16 (4.32–11.87)

 
 

691 (36.64%)

5-9 mm

 

15.97 (9.8–26.01)

 
 

884 (59.81%)

10-19 mm

 

45.47 (27.8–74.37)

 
 

649 (74.51%)

>20 mm

 

109.53 (65.52–183.10)

 

Reason for removal

  

6242

 

<0.001

 

30 (5.12%)

Negative in contact

 

Ref.

 
 

30 (6.55%)

Removed due to IFN-γ result

 

1.32 (0.72–2.38)

 
 

2444 (47.02%)

Removed due to SICCT result

 

20.83 (13.58–31.95)

 

BVD

  

6242

 

0.106

 

2500 (99.84%)

BVD Negative

 

Ref.

 
 

4 (0.16%)

BVD positive

 

0.33 (0.08–1.26)

 

BVD (indirect)

  

6242

 

0.165

 

2407 (40.41%)

BVD Negative

 

Ref.

 
 

97 (33.92%)

BVD positive

 

0.60 (0.29–1.23)

 

Fascioliasis

  

6242

 

0.292

 

2372 (40.33%)

Fascioliasis Negative

 

Ref.

 
 

132 (36.57%)

Fascioliasis Positive

 

0.86 (0.65–1.13)

 

Liver fluke damage

  

6242

 

0.997

 

2161 (40.27%)

Liver damage Negative

 

Ref.

 
 

343 (39.16%)

Liver damage Positive

 

1.00 (0.83–1.2)

 

Liver fluke exposure

  

6242

 

0.55

 

2029 (40.53%)

Facioliasis and damage Negative

 

Ref.

 
 

475 (38.43%)

Facioliasis or damage Positive Mean

 

0.95 (0.81–1.11)

 

Age-quartiles

  

6231

 

<0.001

 

612 (39.74%)

≤ 1.53 years

 

0.77 (0.64–0.92)

 
 

704 (45.48%)

1.53–2.86 years

 

Ref.

 
 

580 (36.64%)

2.86–5.58 years

 

0.69 (0.58–0.83)

 
 

607 (38.91%)

≥5.58 years

 

0.76 (0.63–0.91)

 

Breed

  

6242

 

<0.001

 

1517 (44.29%)

Non-dairy

 

Ref.

 
 

987 (35.04%)

Dairy

 

0.73 (0.61–0.86)

 

Sex

  

6242

 

0.406

 

517 (39.26%)

Male

 

Ref.

 
 

1987 (40.35%)

Female

 

1.07 (0.90–1.26)

 

Associated herds

  

6242

 

<0.001

  

Log(No. associated herds)

 

2.84 (2.45–3.30)

 

No. Market moves

  

6242

 

0.028

  

Market moves

 

1.04 (1–1.08)

 

Time since last test

  

5831

 

<0.001

  

Log(Time in days between tests)

 

1.59 (1.40–1.80)

 

Herd bTB history

  

6242

 

<0.001

 

1188 (35.83%)

No bTB

 

Ref.

 
 

1316 (44.98%)

bTB

 

2.13 (1.76–2.57)

 

Penultimate herd bTB history

  

6242

 

0.044

  

No bTB

 

Ref.

 
  

bTB

 

2.02 (1.02–4.00)

 

Penultimate test results

  

6242

 

<0.001

 

2246 (39.94%)

Severe interpretation negative on penultimate test

 

Ref.

 
 

84 (59.15%)

Severe interpretation positive on penultimate test

 

2.42 (1.57–3.72)

 
 

174 (36.48%)

No previous test result

 

0.84 (0.64–1.09)

 

Breakdown size

  

6242

 

0.001

  

per additional reactor

 

0.99 (0.98–0.99)

 

Herd size

  

6237

 

0.044

(quartiles)

716 (45.99%)

≤71

 

Ref.

 
 

637 (41.26%)

72–158

 

0.86 (0.66–1.1)

 
 

491 (33.22%)

159–279

 

0.71 (0.54–0.93)

 
 

658 (39.69%)

≥280

 

0.72 (0.54–0.94)

 

Purchases

  

6017

 

0.114

(quartiles)

593 (41.61%)

≤7

  

Ref.

 

683 (43.98%)

8–31

 

1.12 (0.86–1.46)

 
 

542 (35.38%)

32–100

 

1.22 (0.91–1.64)

 
 

582 (38.62%)

≥101

 

1.44 (1.06–1.94)

 

Region

  

6242

 

0.171

 

629 (46.35%)

1. North (Derry, Larne, Ballymena and Coleraine)

 

Ref.

 
 

863 (38.2%)

2. South-West (Omagh, Enniskillen and Dungannon)

 

0.91 (0.7–1.18)

 
 

1012 (38.54%)

3. South-east (Newtownards, Newry and Armagh)

 

0.78 (0.61–1.01)

 
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BMC Veterinary Research

ISSN: 1746-6148

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