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 x 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 less than or equal to 0.05) were observed for forage OM, NDF, ADF, and digestible energy. Overall digestibility was lowest for the 7% CP hay and highest for the 10% CP hay. Cecal pH remained above 6.62 irrespective of treatment and time, indicating that cecal pH was suitable for microbial growth. As forage CP level increased, cecal ammonia concentration increased linearly from 0.03 mM for the 7% to 1.74 mM for the 15% CP hay (P < 0.01). Concentration of plasma glucose also linearly increased (P = 0.04) from 68.77 to 73.68 mg/dL as CP concentration increased from 7% to 16% CP. Plasma urea nitrogen exhibited a quadratic effect as concentration increased (P < 0.01) from 4.34 to 5.61 mM for the 7 and 16% CP hays, respectively.

The objective of this study was to determine effects of supplementing coastal bermudagrass (Cynodon dactylon; CBG) hay with Strophostyles helvula (98 g kg-1 crude protein (CP), 476 g kg-1 neutral detergent fiber (NDF)), S. leiosperma (117 g kg-1 CP, 497 g kg-1 NDF), or cottonseed meal (506 g kg-1 CP, 352 g kg-1 NDF; CSM) upon intake of CBG hay (127 g kg-1 CP, 691 g kg-1 NDF) and apparent digestibility of dietary organic matter (OM), NDF, and true digestibility of CP. Six Boer-Spanish goats (46.22 +- 3.99 Kg) were fed CBG plus S. helvula, S. leiosperma, or CSM at 0.34 and 0.68% of BW in a 6*6 Latin square with 3*2 factorial arrangement of treatments. The CBG was fed ad libitum, and the legumes/CSM were fed in two equal daily feedings during a 7-d adjustment period and 7-d collection period in metabolism crates. Feces were collected every 24-h, and CBG, legumes/CSM, and fecal samples were analyzed for OM, NDF, and CP. There were no supplement type*amount interactions (P > 0.05). Supplement type did not affect OM digestibility (P = 0.21), but OM digestibility increased 6.4% (P = 0.05) at the 0.68% versus 0.34% level of supplementation with the legumes or CSM. Supplementation with CSM and S. leiosperma improved NDF digestibility 7% versus supplementation with S. helvula (P = 0.02); and as supplement amount increased NDF digestibility by 5.5% (P = 0.02). The diet supplemented with CSM had the greatest CP digestibility, and S. helvula CP was 6% less digestible than S. leiosperma (P = 0.02). As supplement amount increased, CP digestibility increased 7% (P = 0.01). Intake of DM, OM, and NDF of CBG was unaffected (P = 0.56) by supplementation with CSM, S. helvula, and S. leiosperma, but total diet NDF intake of diets supplemented with CSM and S. helvula was 10.5% less than diet supplemented with S. leiosperma (P = 0.01). Considering digestibility and intake, CSM and S. leiosperma were the best supplements fed in this experiment. Strophostyles leiosperma is recommended as use for diet supplementation for goats when CBG hay basal diet is fed.