An Opportunistic Pilot Study of Radiographs of Equine Nasal Bones at the Usual Site of Nosebands

Restrictive nosebands are of growing concern because of their potential effect on equine welfare. This study evaluates archived radiographs of equine nasal bones for evidence of trauma and to test whether age, sex, or breed were risk factors for such radiographic changes. Radiographs of equine nasal bones (n = 60) were studied for evidence of bony or soft tissue changes by a specialist radiologist blinded to their signalment. Horses with described changes were classified as possible cases and horses without changes, non-cases. The possible cases (n = 9) were discussed with a second specialist radiologist following which the first radiologist reclassified 3 possible cases as non-cases. Radiographs were matched to the age, sex, and breed of each horse and associations with being a case were assessed using Fisher's exact tests. Of 60 horses assessed, 50% of Warmbloods (3/6), 11% of Thoroughbreds (2/18), and 20% of Australian Stock Horses (1/5) were cases. Warmbloods had a greater proportion of changes than other breeds (P = 0.01). There were no statistically significant sex or age associations. The radiologists disagreed as to whether some changes were within normal anatomical variation or were radiographic artifacts but agreed that assessing equine nasal bones using existing radiographs was surprisingly difficult due to issues such as inconsistent radiographic technique and equipment, obliquity of many of the radiographs, and lack of objective data as to what comprises normal nasal bones. Further radiographic studies in this domain should consider the merits of a prospective sample, establish consistent radiography protocols, and aim to establish normality, perhaps by studying a control population that has not had human interventions, such as Australian wild brumbies. (C) 2018 Elsevier Inc. All rights reserved.