Effects of low-fat dried distillers grains on nutrient intake and digestibility in high-concentrate diets

This study aimed to evaluate the effect of including levels of low-fat dried distillers grains without soluble (DDG) in high-concentrate diets on intake and digestibility. Four rumen-cannulated Nellore cattle received four dietary treatments in a 4x4 Latin square experimental design. Treatments included diets without DDG (D0) and varying inclusion levels of DDG at 150 g/kg (D150), 300 g/kg (D300), and 450 g/kg (D450). Four periods of total feces and urine collection were performed to estimate nutrient intake and digestibility and estimate nitrogen balance. Collections of omasum digesta were used to estimate ruminal degradability. The ruminal emptying technique was performed to estimate the ruminal rates of ingestion, passage, and digestion (kd). The inclusion of DDG reduced the intake of total digestible nutrients (TDN) (P < 0.01), dry matter (DM) (P = 0.02), organic matter (OM) (P = 0.02), non-fiber carbohydrates (NFC) (P < 0.01) and ether extract (EE) (P = 0.06). The intake of neutral detergent fiber (NDF) increased linearly (P < 0.01), whereas CP had a quadratic pattern (P = 0.02). The total digestibility in kg/d of DM (P < 0.01), OM (P < 0.01), NFC (P < 0.01) and EE (P = 0.02) decreased linearly. The total digestibility in kg/d of the NDF increased linearly (P < 0.01) and the CP had a quadratic pattern (P = 0.01). The kd of DM (P = 0.01), OM (P < 0.01) decreased linearly and NDF increased linearly (P < 0.01). The amount of N retained did not change (P = 0.72), but the intake of metabolizable protein increased (P = 0.03). Therefore, the inclusion of low-fat DDG in finishing diets reduces TDN intake and reduces the digestibility of almost all nutrients.