Background: Cervical vertebral malformation (CVM) is seen in young, rapidly growing horses, and is commonly associated with a poor prognosis for racing.Hypothesis/Objective: To examine the records of a population of Thoroughbreds with a presumptive diagnosis of CVM and to determine which radiographic findings and neurologic exam findings have an effect on these horses achieving athletic function when managed conservatively.Animals: One hundred and three thoroughbreds presumptively diagnosed with CVM and treated conservatively between 2002 and 2010.Methods: Racing records were reviewed in this retrospective study to determine which horses raced after treatment. Horses were separated into groups based on whether or not they raced. Medical records were reviewed, and results of neurologic examination, radiographic and laboratory findings, treatments, and outcome were assessed and compared between groups.Results: Sixteen horses were excluded because of insufficient information. Of the remaining horses, thirty-three were euthanized after diagnosis, while the remaining seventy were discharged for treatment. Twenty-one of 70 horses treated medically (30%) went on to race. Horses that went on to race had a significantly lower neurologic grade (P = .0002), with a median of 1.0 in the thoracic limbs and 2.0 in the pelvic limbs. Euthanized horses and nonstarters were more likely to have kyphosis (P = .041) or cranial stenosis (P = .041) on standing lateral cervical radiographs.Conclusions and Clinical Importance: Some horses can race after the diagnosis of CVM. Neurologic examination and radiographic findings can be helpful in predicting racing prognosis.

BackgroundDysregulation of the hypothalamic‐pituitary‐adrenal (HPA) axis occurs in horses with systemic inflammatory response syndrome (SIRS). Peripheral resistance to glucocorticoids has not been investigated in horses.ObjectiveTo determine if glucocorticoid receptor (GR) function in horses can be measured using flow cytometry, and to use this information to evaluate HPA axis dynamics.AnimalsEleven healthy adult horses in parts 1 and 2. Ten horses with SIRS and 10 age and sex matched controls in part 3.MethodsFlow cytometry was used to evaluate GR density and binding affinity (BA) in 3 healthy horses in part 1. In part 2, exogenous ACTH was administered to eight healthy horses. Their cortisol response and GR properties were measured. In part 3, CBC, serum biochemistry, cortisol and ACTH, and GR properties were compared between controls without SIRS (n = 10) and horses with SIRS (n = 10), and between survivors and nonsurvivors (n = 4 and n = 6 respectively).ResultsFlow cytometry can be used to measure GR properties in equine PBMCs. No correlation was observed between plasma cortisol concentration and GR density or BA in healthy horses (r = −0.145, P = .428 and r = 0.046, P = .802 respectively). Nonsurvivors with SIRS had significantly decreased GR BA (P = .008). Horses with triglyceride concentration > 28.5 mg/dL had increased odds of nonsurvival (OR=117; 95% CI, 1.94–7,060). GR BA <35.79% was associated with nonsurvival (OR = 30.33; 95% CI, 0.96–960.5).Conclusions and Clinical ImportanceTissue resistance to glucocorticoids contributes to HPA axis dysfunction in adult horses with SIRS. These horses might benefit from treatment with exogenous glucocorticoids.

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