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Table 2 Distribution of herd bulk tank milk antibody percent positivity (PP) values in organically (OM) and conventionally managed (CM) Swedish dairy herds

From: Bovine respiratory syncytial virus and bovine coronavirus in Swedish organic and conventional dairy herds

 

2011

2012

2013

Negative herds a (%)

BRSV

OM (n = 75)

CM (n = 69)

OM (n = 68)

CM (n = 63)

OM (n = 65)

CM (n = 61)

PP < 5

2 (2)

5 (5)

1 (1)

2 (2)

3 (3)

1 (1)

100

5 ≤ PP < 10

1 (1)

0 (0)

2 (2)

3 (3)

3 (3)

3 (2)

92

10 ≤ PP < 30

4 (3)

4 (4)

5 (4)

3 (2)

4 (3)

3 (2)

78

30 ≤ PP < 60

5 (2)

5 (3)

5 (3)

3 (3)

4 (2)

4 (3)

62

60 ≤ PP < 100

18 (2)

20 (5)

41 (3)

34 (3)

22 (2)

28 (3)

11

100 ≤ PP

45 (4)

35 (1)

14 (1)

18 (0)

29 (1)

22 (0)

4

BCoV

       

PP < 5

3 (3)

2 (2)

3 (3)

3 (3)

1 (1)

2 (2)

100

5 ≤ PP < 10

0 (0)

1 (1)

1 (1)

0 (0)

2 (2)

0 (0)

100

10 ≤ PP < 30

4 (4)

2 (2)

1 (1)

2 (1)

3 (3)

4 (3)

88

30 ≤ PP < 60

1 (0)

5 (3)

11 (3)

10 (4)

3 (3)

2 (1)

44

60 ≤ PP < 100

27 (3)

17 (5)

32 (2)

34 (5)

18 (2)

21 (4)

14

100 ≤ PP

40 (1)

42 (3)

20 (1)

14 (1)

38 (3)

32 (0)

5

  1. The figures in brackets indicate the number of herds in each group where samples from all four individual were negative (PP < 10).
  2. aTotal proportions, i.e. over three sampling occasions, of sampled herds where also the four individuals were negative (PP < 10).