Faced with that scenario, a dose of two grams a day should not be exceeded, and that dose should be in the oral form. In addition, the animal should be monitored carefully for the duration of the treatment. I have had broodmares with laminitis who would not stay on their feet without daily treatment with Bute, which were maintained on this sort of dosage regimen all through pregnancy. Foals from these mares were typically normal and showed no ill effects from their dams' treatment. The mares usually improved somewhat after delivery.
Young horses appear to be more susceptible to the problems of phenylbutazone toxicity.
Foals and yearlings with inflammatory disorders should be managed very carefully with regard to anti-inflammatory medication. But, there is always the potential for trouble when too much of a good thing is used for too long. Horse owners should work closely with their veterinarians in the management of these problems. A.C. Asbury, DVM, retired to Versailles, Ky., after a practice and academic career devoted to equine reproduction.