Fibrous osteodystrophy in a Lavradeira filly associated with Brachiaria humidicola ingestion

Abstract

Fibrous osteodystrophy in horses is due to low calcium ingestion, high phosphorus ingestion, high oxalate ingestion, or a combination of these. Tropical forages usually have high levels of oxalates, which prevents calcium absorption and results in calcium deficiency. The present study reports a case of fibrous osteodystrophy in a filly associated with Brachiaria humidicola ingestion. A 1-year-old filly of the Lavradeiro breed was maintained on a pasture with B. humidicola and presented bilaterally enlarged facial bones, a high respiratory rate, noises during inspiration-expiration and dyspnea. Based on its history, age and clinical signs, the diagnosis was fibrous osteodystrophy associated with B. humidicola ingestion. Treatment was based on the administration of calcium gluconate, vitamins A, D and E, and clenbuterol. All other horses were transferred to a field with native forage and were supplemented with calcium carbonate. In Roraima state, the use of tropical forages in equine feeding is very common and represents a risk factor for the occurrence of fibrous osteodystrophy due to the continuous ingestion of oxalates. In horses, the diagnosis is achieved by clinical exam and treatment aims to correct the imbalance in Ca:P ratio, associated with support therapy.