Performance and milk composition of Holstein cows fed increasing levels of dried distillers' grains with solubles.

The objective was to evaluate the performance and milk composition of cows fed diets containing dried distillers' grains with solubles (DDGS). Five multiparous Holstein cows were distributed in a 5 × 5 Latin square. The treatments involved inclusion levels of 0%, 8%, 16%, 24%, and 32% of DDGS from corn in the diet. The inclusion of DDGS in the diet reduced the intake of dry matter (DM), crude protein (CP), and non-fibrous carbohydrates (NFC), and increased the intake of ether extract (EE) and neutral detergent fiber (NDF) (P < 0.05). However, the energy intake was unchanged, which can be explained by the increased digestibility of nutrients. There was a quadratic effect (P < 0.05) on digestibility of DM and NFC, and NDF digestibility increased linearly with the inclusion of DDGS in the diet. Possibly, the reduction of ingested DM promoted a decrease in the passage rate of feed through the...