Effects of time and level of energy supplementation on intake and digestibility of low-quality tall fescue hay by sheep

Effects of time and level of energy supplementation on forage intake, nutrient digestibility and ruminal pH were investigated with sheep fed low-quality tall fescue hay either alone (control; C) or supplemented (S) with concentrate at 10 (low; L) or 20% (high; H) of ad libitum forage intake; supplement was offered at 08:00 or 15:00 h. Supplementation increased (P < 0.05) digestible dry matter intake (DMI), total tract organic matter digestibility, N intake, and N digestibility, but decreased (P < 0.05) mean and minimum ruminal pH compared with C. Offering supplement at 08:00 h increased (P < 0.05) forage and total DMI, N intake, fecal N excretion and maximum ruminal pH, but lowered (P < 0.05) total tract digestibility of acid detergent fibre (ADF) and organic matter, and mean and minimum ruminal pH compared with 15:00 h. A high level of supplementation increased (P < 0.10) digestible DMI, postruminal digestion of neutral detergent fibre (NDF), and hemicellulose (HC), but lowered (P < 0.01) ruminal digesti...