Table 2 Descriptive characteristics of the variables included in the models (100 herds in Model I and 77 herds in Model II)

Model I

Model II

Nasal discharge ("red nose") in cows and/or pregnant heifers

0 - not present at all or was shown only as single cases at some point during the last two years

82

(NASCOW)

1 - present in more than just single cases at some point during the last two years

18

Respiratory symptoms (cough, dyspnoea) in cows and/or pregnant heifers

0 - not present at all or was shown only as single cases at some time point during the last two years

80

(RESCOW)

1 - present in more than just single cases at some point during the last two years

20

Lacrimation in cows and/or pregnant heifers

0 - not present at all or was shown only as single cases at some point during the last two years

88

(LACCOW)

1 - present in more than just single cases at some point during the last two years

12

Respiratory disease occurrence in cows and/or pregnant heifers

0 - less than two respiratory disease symptoms were present in more than a single case at some time during the last two years

81

(BRDCOW)

1 - at least two respiratory disease symptoms were present in more than a single case at some time during the last two years

19

Incidence of abortions in the herd

0 - < 1.3% in a herd (median for cut-off value)

37

(ABORT)

1 - ≥ 1.3% in a herd

40

Insemination index for cows and heifers

0 - < 1.9 in a herd (median for cut-off value)

38

(INSIN)

1 - ≥1.9 in a herd

39

Herd size

3 - 20-99 cows

40

25

(hsize)

4 - 100-199 cows

19

17

5 - 200-399 cows

23

21

6 - > 400 cows

18

14

Veterinarian an employee of the farm

0 - no

77

(vetemp)

1 - yes

23

Does the inseminator give service to other farms

0 - no

28

(insoth)

1 - yes

72

Inseminator an employee of the farm

0 - no

56

(insemp)

1 - yes

44

Using bull to inseminate heifers

0 - no

61

(bullh)

1 - yes

39

Keeping youngstock together with cows

0 - together

51

(yoco)

1 - in separate building from 6 months until pregnancy

49

Housing for youngstock

1 - tied

23

(keyo)

2 - loose

30

3 - some period of life tied, some period loose

47

Housing for cows

1 - tied

71

(keco)

2 - loose

29

Has the farm purchased new animals within the last three years

(purc)

0 - no

1 - yes

47

53

BVDV present in the herd

0 - no

77

57

(BVD)

1 - yes (at least one animal tested positive)

23

20

RSV prevalence

0 - negative

46

34

(BRSV)

1 - 1 - 49%

40

33

2 - ≥50%

14

10

BHV-1 prevalence in cows

0 - negative

37

25

(BHVcow)

1 - 1 - 49%

28

24

2 - ≥50%

35

28

BHV-1 prevalence in heifers

0 - negative

56

40

(BHVheif)

1 - positive

44

37