Table 2 Logistic regression model for intrinsic and extrinsic variables related to heel bruising in piglets at 5 days of age

Piglet's sex

p = 0.2030

p = 0.3527

 Female

270

52.63

243

47.37

1

 × 

 × 

1

 × 

 × 

 Male

270

53.68

233

46.32

1.282

0.874

1.879

1.211

0.809

1.812

Litter size

p = 0.8651

p = 0.9083

  < 16

283

53.00

251

47.00

1

 × 

 × 

1

 × 

 × 

  ≥ 16

283

54.32

238

45.68

0.909

0.30

2.730

0.960

0.480

1.920

Floor

p < 0.0001

p < 0.0001

 RML*

443

82.80

92

17.20

1

 × 

 × 

1

 × 

 × 

 PSL*

123

24.12

387

75.88

40.590

21.133

77.961

52.891

26.286

106.425

Body weight day 1 (kg)

p = 0.0003

p = 0.0006

  ≤ 1.20

185

58.18

133

41.82

1

 × 

 × 

1

 × 

 × 

 1.21–1.50

161

51.94

149

48.06

2.543

1.510

4.281

2.541

1.472

4.385

  ≥ 1.51

151

49.51

154

50.49

3.085

1.677

5.676

3.071

1.626

5.801

Average daily gain until day 5 (kg)

p = 0.0454

p = 0.7105

  ≤ 0.110

157

53.04

139

46.96

1

 × 

 × 

1

 × 

 × 

 0.111–0.0160

173

56.17

135

43,83

1.136

0.694

1.859

1.092

0.661

1.802

  ≥ 0.161

158

51.47

149

48.53

1.911

1.108

3.294

1.275

0.713

2.281