Table 4 Bivariable analysis of categorical predictors for predicted calving rate in herds in three states of Northern Nigeria

Brucella infection^a

<0.001

 No

59

76.8

9.2

 Yes

192

43.6

21.8

Campylobacter fetus infection^a

<0.001

 No

166

57.3

22.2

 Yes

66

33.1

18.0

State^a

0.033

 Adamawa

87

46.1

23.5

 Kaduna

98

55.2

22.8

 Kano

66

52.7

25.8

Method of breeding^a

0.026

 AI and natural mating

44

52.5

24.0

 AI only

11

70.1

25.0

 Natural mating only

196

50.1

23.8

Use of AI^a

0.11

 No

196

50.1

23.8

 Yes

55

56.0

25.0

Management system^a

<0.001

 Zero-grazing

3

76.2

12.3

 Commercial

26

66.2

25.4

 Agro-pastoral

146

58.1

21.3

 Pastoral

76

32.6

17.3

Supplementary feeding^a

<0.001

 None

25

21.9

7.6

 Fodder/bran

105

46.3

22.1

 Concentrate

121

62.0

21.5

Mineral supplementation^a

<0.001

 No

69

32.2

17.6

 Yes

182

58.7

22.2

Pasture establishment^a

0.122

 No

187

50.0

23.8

 Yes

64

55.5

24.9

Water source^a

<0.001

 Piped

69

63.2

21.2

 Natural flowing

112

46.6

22.5

 Natural static

70

47.6

25.8

Housing^a

<0.001

 Open barbed wire

153

46.4

23.3

 Open half way and roofed

66

63.1

24.6

 Open solid enclosure

32

51.5

18.9

Hygiene/floor type^a

<0.001

 Floored

63

63.1

23.0

 Unfloored/natural bear earth

188

47.5

23.3

Isolation and observation of the cow during parturition and removal of afterbirth^a

<0.001

 No

94

35.1

19.1

 Yes

154

61.4

21.4

Regular herd prophylactic measures^a

<0.001

 No

97

40.0

22.1

 Yes

154

58.6

22.5

Borrow/share bull^a

<0.001

 No

166

60.4

21.8

 Yes

85

33.9

18.2

Presence of small ruminants^a

<0.001

 No

97

65.6

19.5

 Yes

154

42.5

22.5

Presence of dogs^a

0.036

 No

227

52.9

24.5

 Yes

24

37.5

13.7

Presence of chickens^a

0.0002

 No

161

55.7

23.3

 Yes

90

43.8

23.9

Multiple herds^a

0.013

 No

166

54.1

23.6

 Yes

85

46.1

25.3

Purpose of keeping animals^a

0.0002

 Small scale local dairy

187

52.5

24.1

 Dairy and Beef

29

61.3

23.2

 Beef

35

37.5

18.9

Initial purchase of stock from a market^a

<0.001

 Inherited

118

55.1

24.0

 Other farms

14

71.5

21.2

 Market

119

45.4

27.7

Buying-in new animals and quarantine^a

<0.001

 Buy <3 + quarantine

30

68.4

11.8

 Buy >3 or no quarantine

147

38.3

20.2

 Close herd

74

70.6

15.9

Socio-economic status of farmer^a

0.031

 Full-time

176

53.6

23.7

 Part-time

75

46.4

24.9

Specialist attending to animals^a

<0.001

 No

48

32.6

17.9

 Yes

203

55.9

23.3

Presence of crush/local chute or other means of handling/restrain at the farm^a

0.061

 No

187

49.8

23.9

 Yes

64

56.3

24.9