Abstract

Decomposed granite (DG), also known as crushed granite, is a construction and landscaping material commonly used in zoos as a base for flamingo exhibits. Since 2008, the Fort Worth Zoo has used synthetic grass (turf) over a compacted layer of DG in the flamingo exhibit. In 2013, the turf was removed, pressure washed, and the DG replaced. The turf was then re-stretched in place. Few months later, a number of flamingos presented with lethargy, poor body condition, anemia and hypoproteinemia. Radiographs revealed radiopaque material in the ventriculus and dilated intestinal loops. Necropsy showed granite-like material in ventriculus, severe congestion of intestinal mucosa and obstruction of intestinal lumen by caseous plugs surrounded by fecal material. Histopathology revealed marked chronic erosive colitis, mild erosive proventriculitis and hypercontraction of the muscular tunics of ventriculus. Radiographic screening of 82 flamingos revealed 64.5% with moderate amount of radiopaque material, 25.6% with large amount, 8.53% with small amount and 1.2% did not have any material. Flushing the ventriculus per os in the Trendelenburg position and by esophagostomy tube yielded poor results, as did the attempt to endoscopically remove the material. Medical treatments included antibiotics in water, cathartic drugs, contrast agents or a combination thereof. Screening radiographs were repeated in all birds to evaluate changes in material content. Before the birds were released back into the exhibit, the soil substrate beneath the artificial grass was completely removed and replaced with a concrete surface (sloped to a drain) and topped with a layer of Dri-Dek® before the original turf was re-applied.

Acknowledgments

The authors thank the veterinary technicians and the bird department at the Fort Worth Zoo for their invaluable assistance during the flock assessment and treatments.