Routine laboratory work including serum chemistry and urinalysis.

       Transient increase RBC for 1 hour post‐administration.

       Mild increase in lactate and glucose within 1 hour of administration.

       RBCs and urinary epithelial cells in urine.

       ± hypocalcemia.

       Specialized testing for elevated cTnI within 24–48 hours of administration.

       ECG as needed for tachycardia and cardiac effects.

       Presence in serum and urine:No rapid, commercially available urine tests.ICP‐MS useful for diagnosis, but the time delay would hinder therapeutics.

       No specific lesions reported in horses.

       The goal of therapy is to provide supportive care.

       Large ingestions – gastric lavage or reflux with large‐bore tube.

       Supportive care if symptomatic.

       Most can be treated in the field.

       Most clinical parameters return to baseline within 2 hours.

       No specific antidote.

       IV fluids as needed for dehydration and volume expansion; may be helpful to increase elimination.

       Agitation:Acepromazine 0.01–0.05 mg/kg IV, IM, SC prn.Adrenergic agonist: detomidine 10–40 μg/kg IM, IV or xylazine 0.5–1 mg/kg IV.

       GI protectants:Omeprazole 2–4 mg/kg PO q24h.

        Tremors, twitching:Acepromazine 0.01–0.05 mg/kg IV, IM, SC prn/Methocarbamol 4.4–22.2 mg/kg IV to effect. Administer half estimated dose and pause until the horse has relaxed. Administer the remainder of the dose to effect. Repeat as needed but do not exceed 330 mg/kg/day.

       Protection to the head and limbs may be necessary in severely agitated horses.

       There is no purpose for cobalt supplementation in horses.

       ICP‐MS may be useful in legal cases.

       Educate trainers and owners about the adverse effects in horses.

       Acute kidney injury.

       Cardiac damage.

       Injury due to ataxia/colic.

       Long‐term potential to cause arrhythmias resulting in sudden death.

       Toxicity – for experimentally induced cases, prognosis is good with effects generally subsiding after 2 hours.

       Fatality – prevalence of fatality in clinical cases is unknown as reports are limited.

      1 Racing Medication and Testing Consortium, Cobalt. Available at: https://rmtcnet.com/wp‐content/uploads/2015‐10‐Cobalt‐Brochure.pdf (accessed January 15, 2021).

      2 European Food Safety Authority, Scientific Opinion on Safety and Efficacy of Cobalt Carbonate as Feed Additive for Ruminants, Horses and Rabbits. Available at: https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2012.2727 (accessed January 15, 2021).

      1 Burns TA, Dembek KA, Kamr A, et al. Effect of intravenous administration of cobalt chloride to horses on clinical and hemodynamic variables. J Vet Intern Med 2018; 32:441–449.

      2 Knych, HK, Arthur, RM, Mitchell MM, et al. Pharmacokinetics and selected pharmacodynamics of cobalt following a single intravenous administration to horses. Drug Test Anal 2015; 7:619–625.