Table 7 The summary of the sub-group analysis on the effects of probiotics on pre-weaning dairy calves

BW

 All trials

55

1.885

1.009, 2.761

 < 0.001

45.5

 < 0.001

 Methods

Milk replacer

30

0.847

−0.127, 1.822

0.088

50.2

0.151

starter

2

1.663

−0.378, 3.704

0.110

0.0

0.094

Whole milk

23

4.439

2.581, 6.297

 < 0.001

31.0

 < 0.001

TDMI

 All trials

39

0.023

0.009, 0.037

0.001

73.5

0.001

 Strains

Compound

24

0.028

0.011, 0.046

0.002

76.9

0.001

Single

15

0.013

−0.013, 0.040

0.332

66.7

0.329

 Methods

Milk replacer

20

0.019

0.001, 0.037

0.044

64.3

0.030

starter

8

0.002

−0.021, 0.025

0.873

0.0

0.379

Whole milk

11

0.033

0.007, 0.058

0.014

87.0

0.018

Butyrate

 All trials

13

0.828

0.312, 1.345

0.002

55.5

 < 0.001

 Dosage(log)

low (< 9)

5

2.762

0.161, 5.363

0.037

69.9

0.022

high (> 10)

8

0.463

0.037, 0.889

0.033

47.8

0.013

IgA

 All trials

20

0.296

0.191, 0.400

 < 0.001

73.8

 < 0.001

 Dosage(log)

low (< 9)

3

0.040

−0.083, 0.163

0.523

0.0

0.533

middle (9.5–9.9)

11

0.219

0.093, 0.345

0.001

68.3

0.015

high (> 10)

6

0.618

0.295, 0.942

 < 0.001

74.3

 < 0.001

 Strains

Compound

15

0.471

0.283, 0.659

 < 0.001

62.9

 < 0.001

Single

5

−0.000

−0.058, 0.057

0.987

64.0

0.925

 Methods

Milk replacer

7

−0.017

−0.047, 0.013

0.268

0.0

0.441

Whole milk

13

0.554

0.367, 0.741

 < 0.001

42.2

 < 0.001

IgM

 All trials

21

0.255

0.152, 0.358

 < 0.001

72.9

 < 0.001

 Dosage(log)

low (< 9)

3

−0.037

−0.126, 0.052

0.420

0.0

0.424

middle (9.5–9.9)

11

0.266

0.130, 0.402

 < 0.001

69.1

 < 0.001

high (> 10)

7

0.400

0.218, 0.582

 < 0.001

73.4

0.001

 Strains

Compound

15

0.324

0.192, 0.457

 < 0.001

73.2

 < 0.001

Single

6

0.255

0.152, 0.358

0.848

0.0

0.354

 Methods

Milk replacer

7

−0.006

−0.031, 0.019

0.653

0.0

0.892

Whole milk

14

0.408

0.317, 0.499

 < 0.001

59.5

 < 0.001

Faecal score

 All trials

24

−0.047

−0.083, −0.011

0.011

68.8

0.031

 Age

young(≤ 5)

17

−0.030

−0.084, 0.024

0.275

70.3

0.266

old(≥ 10)

7

−0.061

−0.105, −0.018

0.006

52.7

0.010

 Duration

short (≤ 28)

12

0.012

−0.059, 0.082

0.747

36.6

0.626

long (≥ 42)

12

−0.070

−0.113, −0.026

0.002

73.5

0.002

 Methods

Milk replacer

14

−0.051

−0.089, 0.014

0.007

70.1

0.018

starter

6

0.126

0.025, 0.227

0.014

0.0

0.017

Whole milk

4

−0.158

−0.273, −0.043

0.007

66.6

0.029