Table 1 Final multivariable Cox regression model for variables associated with active episodes of owner-reported laminitis (n = 100) in a cohort of British horses and ponies (n = 978 horses/ponies providing 6390 observations and a cumulative time of 974 HYAR after exclusions for missing data)
Variable | No. laminitis episodes | HYAR/100 | Hazard ratio | 95% CI | Wald P-value | LRS P-value |
|---|---|---|---|---|---|---|
Animal-level factors | ||||||
 Weight change since last entry |  |  |  |  |  | 0.003 |
  Weight lost/maintained | 68 | 7.6 | Ref. |  |  |  |
  Weight gained | 30 | 2.0 | 2.3 | 1.4, 3.8 | < 0.001 |  |
  Not specified | 2 | 0.1 | 1.8 | 0.4, 8.0 | 0.44 |  |
 Breed category (including breed crosses) |  |  |  |  | 0.007 | |
  Native pony | 65 | 3.8 | 1.9 | 1.2, 3.0 | 0.007 |  |
  Other breed | 35 | 5.9 | Ref. |  |  |  |
Laminitis history | ||||||
 Previous laminitis while with current owner |  |  |  |  | < 0.001 | |
  No | 23 | 6.4 | Ref. |  |  |  |
  Yes, veterinary-diagnosed | 44 | 2.4 | 1.7 | 0.8, 3.8 | 0.15 |  |
  Yes, not veterinary-diagnosed | 33 | 0.9 | 4.5 | 2.2, 9.1 | < 0.001 |  |
 Time taken to return to soundness following most recent episode |  | 0.002 | ||||
  0 to 2 weeks | 38 | 7.4 | Ref. |  |  |  |
  More than 2 weeks to 2 months | 32 | 1.3 | 2.0 | 1.0, 3.8 | 0.04 |  |
  More than 2 months | 30 | 1.0 | 3.1 | 1.6, 6.2 | 0.001 |  |
Health management and recent health history | ||||||
 Currently on steroidal anti-inflammatories |  |  |  |  | 0.03 | |
  No | 96 | 9.6 | Ref. |  |  |  |
  Yes | 4 | 0.1 | 4.0 | 1.4, 11.6 | 0.01 |  |
 Currently on non-steroidal anti-inflammatories |  |  | < 0.001 | |||
  No | 77 | 8.9 | Ref. |  |  |  |
  Yes | 23 | 0.8 | 2.9 | 1.7, 4.8 | < 0.001 |  |
 Current lameness |  |  |  |  |  | 0.02 |
  Other lameness/no lameness | 95 | 9.6 | Ref. |  |  |  |
  Soft tissue injury (e.g. tendon/ligament) | 5 | 0.2 | 4.1 | 1.5, 10.8 | 0.005 |  |
 Active wormer ingredients in last wormer given |  |  | 0.003 | |||
  Macrocyclic lactones | 19 | 2.4 | Ref. |  |  |  |
  Benzimidazoles | 15 | 0.5 | 3.8 | 1.8, 8.1 | < 0.001 |  |
  Other/no wormer | 66 | 6.8 | 1.3 | 0.7, 2.2 | 0.39 |  |
Hoof care | ||||||
 Lameness/soreness following routine hoof care |  |  | 0.004 | |||
  Not lame/sore after shoeing/trimming | 83 | 9.3 | Ref. |  |  |  |
  Lame/sore after shoeing/trimming | 17 | 0.4 | 2.5 | 1.4, 4.4 | 0.002 |  |
 Trimming/shoeing frequency |  |  |  |  |  | 0.03 |
  Up to 8 weeks | 80 | 8.3 | Ref. |  |  |  |
  More than 8 weeks | 20 | 1.4 | 1.9 | 1.1, 3.2 | 0.02 |  |
Turnout and grazing management | ||||||
 Time of day access to grass currently available |  |  | 0.007 | |||
  Morning only | 9 | 0.4 | 4.3 | 1.8, 10.8 | 0.002 |  |
  Day and night | 28 | 4.7 | Ref. |  |  |  |
  Other/grass not available | 63 | 4.7 | 1.4 | 0.7, 2.8 | 0.28 |  |
 Grazing muzzle use |  |  |  |  |  | 0.001 |
  Whole time while grazing/not used | 89 | 9.5 | Ref. |  |  |  |
  Part of the time while grazing | 11 | 0.3 | 3.6 | 1.8, 7.2 | < 0.001 |  |
 Woodland bordering turnout area |  |  |  |  |  | 0.007 |
  No/entirely stabled | 82 | 7.1 | Ref. |  |  |  |
  Yes | 18 | 2.6 | 0.5 | 0.3, 0.9 | 0.01 |  |
 Main reason for transport in the previous year |  |  |  |  | 0.001 | |
  Other reason/not transported | 82 | 8.7 | Ref. |  |  |  |
  Moving yards | 18 | 1.0 | 2.6 | 1.5, 4.5 | < 0.001 |  |
 Average time currently spent stabled |  |  |  |  |  | < 0.001 |
  Up to 12 h | 46 | 2.7 | 3.2 | 1.7, 5.9 | < 0.001 |  |
  More than 12 h | 19 | 2.1 | Ref. |  |  |  |
  Free access/not stabled | 35 | 4.9 | 1.7 | 0.8, 3.7 | 0.15 |  |
Supplementary feeding | ||||||
 Ryegrass forage fed |  |  |  |  |  | < 0.001 |
  Other/no forage fed | 91 | 9.3 | Ref. |  |  |  |
  Yes | 9 | 0.5 | 4.7 | 2.2, 10.0 | < 0.001 |  |