Laminitis is a complex disorder that is difficult to diagnose before the onset of lameness. Ten horses were allocated into 2 experimental groups: The 5 animals of GI did not undergo carbohydrate overload (control group) whereas the remaining 5 in GII underwent carbohydrate overload (laminitis group). After carbohydrate was provided to the animals, clinical and laboratorial examination were performed over a 48-hour period. The hoof tissues underwent histological assessment at the end of study. The digital pulse increased from 12 hours on, simultaneous to initial signs of lameness, which increased to Obel grade 3 after 24 hours. Change of external maxilar artery pulse was noted to 24 hours; at the same time an increase of the capillary refill time was seen. It was verified that heart rate and internal temperature increased 36 hours after overfeeding. Eosinopenia occurred 12 hours after carbohydrate overload. The packet cell volume changed after 36 hours, concomitantly with neutrophilia. Mild leucocytosis occurred during the experiment. The changes of the plasma total protein and fibrinogen concentrations and serum aspartate aminotransferase activity were not significant. Although not expected, the serum creatine kynase activity was highest in control group. The serum alkaline phosphatase activity was highest in laminitis group. The major histological changes were degenerative, including vascular congestion, thrombosis, and basement membrane degeneration.
KEYWORDS: Carbohydrate. Equine. Laminitis. Signs. Hematology. Serum biochemistry.