Effects of crude protein content on intake and digestion of coastal bermudagrass hay by horses

Effects of Crude Protein Content on Intake and Digestion of Coastal Bermudagrass Hay by Horses. (May 2010) Chelsey Lynn Spurgin, B.S., Texas A&M University Co-Chairs of Advisory Committee: Dr. Tryon Wickersham Dr. Josie Coverdale This study was conducted to determine the effect of forage CP level on intake and digestion of Coastal bermudagrass hay by horses. Four cecally fistulated geldings were used in a 4 × 4 Latin square design with four treatments and four periods. Horses were fed one of four Coastal bermudagrass hays consisting of 7, 10, 13, or 16% CP during each of the 4 15-d periods. Intake and apparent digestibility were determined for each horse at the end of each period by total fecal collection. In addition, cecal fluid and blood samples were collected from each horse on the last day of each period for determination of cecal ammonia, cecal pH, plasma urea nitrogen, and plasma glucose concentrations. Crude protein concentration of Coastal bermudagrass hay influenced equine intake and digestion. Increasing CP concentration linearly increased digestible OM intake (DOMI) from 3.79 to 5.98 kg/d for 7 and 16% CP hay, respectively (P = 0.04). Furthermore, as forage CP level increased, CP intake increased linearly (P < 0.01). Forage CP level had no effect on forage DM intake. Quadratic effects (P 0.05) were