Table 1 Descriptive statistics and unadjusted univariable associations from logistic regression models between animal-level BVD serology test status and temporal, animal-, and herd-level independent variables

TEMPORAL

 Year

  2017

1071 (91.15)

104 (8.85)

1175

1.000

referent

  2018

2286 (94.42)

135 (5.58)

2421

0.608

0.466

0.793

 < 0.001

  2020

2742 (96.11)

111 (3.89)

2853

0.417

0.316

0.550

 < 0.001

ANIMAL LEVEL

 Age – months (quartiles)

  10–23

1500 (93.05)

112 (6.95)

1,612

1.000

referent

  24–25

1284 (95.11)

66 (4.89)

1,350

0.688

0.019

0.503

0.942

  26–27

1365 (93.88)

89 (6.12)

1,454

0.873

0.356

0.655

1.164

  28–30

1950 (95.92)

89 (4.08)

2,033

0.570

0.000

0.426

0.763

 Breed

  Aberdeen Angus

1,116 (94.98)

59 (5.02)

1175

1.000

referent

  Charolais

1,124 (95.09)

58 (4.91)

1182

0.976

0.673

1.416

0.898

  Friesian

1,170 (93.23)

85 (6.77)

1255

1.374

0.976

1.935

0.069

  Hereford

892 (94.99)

47 (5.01)

939

0.997

0.673

1.477

0.987

  Limousin

1,137 (94.51)

66 (5.49)

1203

1.098

0.765

1.575

0.612

  Other

660 (94.96)

35 (5.04)

695

1.003

0.653

1.541

0.989

 Sex

  Male

3513 (95.44)

168 (4.56)

3681

0.679

0.548

0.843

 < 0.001

  Female

2,586 (93.42)

182 (6.58)

2768

1.000

referent

 Movement (different last herd to birth herd)

  No

1733 (94.49)

101 (6.51)

1,834

1.000

referent

  Yes

4366 (94.6)

249 (5.43)

4,615

0.979

0.771

1.241

0.858

 Moved during previous year

  No

1677 (94.59)

96 (5.41)

1,773

1.000

referent

  Yes

4422 (94.57)

254 (5.43)

4,676

1.003

0.735

1.370

0.983

HERD LEVEL

 Herd Type (last)

  Beef

337 (92.84)

26 (7.16)

363

1.160

0.761

1.770

0.489

  Dairy

3,264 (93.77)

217 (6.23)

3481

1.000

referent

  Suckler

2,192 (96.31)

84 (3.69)

2276

0.576

0.446

0.746

 < 0.001

  Other

306 (93.01)

23 (6.99)

329

1.131

0.724

1.765

0.589

 Birth Herd size (quartiles)

  < 60 (mean: 33.7)

1515 (95.83)

66 (4.17)

1,581

referent

  60–119 (mean:88.9)

1548 (94.39)

92 (5.61)

1,640

1.364

0.987

1.886

0.06

  120–201 (mean: 157.4)

1536 (95.17)

78 (4.83)

1,614

1.166

0.834

1.630

0.37

  202–1574 (mean: 352.7)

1500 (92.94)

114 (7.06)

1,614

1.745

1.278

2.382

 < 0.001

 Last Herd size (quartiles)

  < 52 (mean: 28.9)

1537 (96.00)

64 (4.00)

1,601

referent

  53–109 (mean: 80.6)

1543 (95.66)

70 (4.34)

1,613

1.089

0.771

1.540

0.628

  110–225 (mean: 160.3)

1519 (93.88)

99 (6.12)

1,618

1.565

1.134

2.160

0.006

  226–3755 (mean: 451.2)

1500 (92.76)

117 (7.24)

1,617

1.873

1.370

2.561

 < 0.001

 PI Birth herd year status

  Absent

5890 (95.52)

276 (4.48)

6166

1.000

referent

  Present

209 (73.85)

74 (26.15)

283

7.556

5.339

10.694

 < 0.001

 PI Last herd year status

  Absent

6003 (94.92)

321 (5.08)

6,324

1.000

referent

  Present

96 (76.8)

29 (23.2)

125

5.649

3.674

8.686

 < 0.001