Table 1.
Herd-level predictors on BDD collected from 127 New Zealand dairy herds
| Variable | Levels | Herds with BDD lesions N (%) | Herds without BDD lesions N (%) | Total |
|---|---|---|---|---|
| Type of milking parlour | Rotary | 29 (51%) | 28 (49%) | 57 |
| Herringbone | 34 (49%) | 36 (51%) | 70 | |
| Calving season | Spring only | 57 (49%) | 59 (51%) | 116 |
| Spring and Autumn | 6 (55%) | 5 (45%) | 11 | |
| Whether or not having dairy cattle milking on more than one farm | Yes | 9 (14%) | 6 (9%) | 15 |
| No | 54 (48%) | 58 (52%) | 112 | |
| Source of acquired adult cows (> 2 years old) | Other farms | 8 (62%) | 5 (38%) | 13 |
| Saleyard | 2 (50%) | 2 (50%) | 4 | |
| Not acquiring | 53 (48%) | 57 (52%) | 110 | |
| Source of acquired bulls | Other farms | 36 (47%) | 41 (53%) | 77 |
| Saleyard | 9 (64%) | 5 (36%) | 14 | |
| Not acquiring | 18 (50%) | 18 (50%) | 36 | |
| Source of acquired heifers | Other farms | 15 (68%) | 7 (32%) | 22 |
| Saleyard | 1 (50%) | 1 (50%) | 2 | |
| Not acquiring | 47 (46%) | 56 (54%) | 103 | |
| Whether your calves/heifers co-grazing with calves/heifers from other farms | Yes | 46 (59%) | 32 (41%) | 78 |
| No | 17 (35%) | 32 (65%) | 49 | |
| Whether your milking dairy cattle co-grazing with cows from other farms in winter | Yes | 28 (57%) | 21 (43%) | 49 |
| No | 35 (45%) | 43 (55%) | 78 | |
| Providing grazing for stock from other farms at your farm or not | Yes | 3 (50%) | 3 (50%) | 6 |
| No | 60 (50%) | 61 (50%) | 121 | |
| Using a transport company to transport animals (not for slaughter) or not | Yes | 43 (49%) | 45 (51%) | 88 |
| No | 20 (51%) | 19 (49%) | 39 | |
| Share a loading ramp or not | Yes | 7 (41%) | 10 (59%) | 17 |
| No | 56 (51%) | 54 (49%) | 110 | |
| Who did most of the hoof trimming/ lame cattle treatment on your farm | Vet | 7 (39%) | 11 (61%) | 18 |
| Hoof trimmer | 6 (86%) | 1 (14%) | 7 | |
| On-farm staff | 50 (49%) | 52 (51%) | 102 | |
| Trimming equipment cleaning methods | Washed by water | 28 (51%) | 27 (49%) | 55 |
| Chemically disinfected | 11 (55%) | 9 (45%) | 20 | |
| Not wash | 24 (46%) | 28 (54%) | 52 | |
| Use a footbath or not | Yes | 10 (63%) | 6 (37%) | 16 |
| No | 53 (48%) | 58 (52%) | 111 | |
| Whether or not use stand-off pads or cow houses in winter or poor weather | Stand-off pad | 18 (49%) | 19 (51%) | 37 |
| Cow house | 2 (22%) | 7 (78%) | 9 | |
| Neither | 43 (53%) | 38 (47%) | 81 | |
| Main material of the walking track/race from paddock to the milking parlour | Gravel | 22 (35%) | 40 (65%) | 62 |
| Concrete | 1 (50%) | 1 (50%) | 2 | |
| Other | 40 (63%) | 23 (37%) | 63 | |
| Use feedpad or not | Yes | 23 (48%) | 25 (52%) | 48 |
| No | 40 (51%) | 39 (49%) | 79 |
BDD, bovine digital dermatitis; N (%), numbers of herds having such a predictor (row percentage of herds having such a predictor)
Average herd milk solid production in BDD-lesion positive/negative herds were 414.9 kg/cow year and 414.1 kg/cow year, respectively