Effects of Replacing Corn and Soybean Meal with Dried Distillers Grains with Solubles on Blood Metabolites, Milk Composition and Fatty Acid Profile of Dairy Goats Consuming Eastern Gamagrass Hay During Late Lactation.

In the southern USA warm season grasses make up the bulk of the roughage consumed by livestock including small ruminants. Digestibility of grasses generally declines with maturity, such that these forages may not always provide the necessary nutrients to support optimal animal performance or maintain product quality. Supplementation with protein and moderate level of grain generally increases forage intake and digestibility. The diversion of corn away from human and animal feed for biofuel production has created a need for alternative energy supplements. Dried distillers grains with solubles (DDGS), high in bypass protein and digestible fiber, is a good alternative to replace corn and soybean meal (SBM) in small ruminant diets. The objective of this study was to determine intake, blood metabolites and milk composition of dairy goats (Alpine), in late lactation, consuming ground eastern gamagrass (EG; Tripsacum dactyloides L.) hay supplemented with DDGS or corn and SBM. The does were stratified based on milk yield and allotted to 4 groups. The groups were randomly assigned to 1 of 2 treatments (10 does/trt). The groups were housed in 4 pens equipped with Calan gate feeders (American Calan, Inc.) and fed once daily to allow ad libitum intake. Hay was fed ad libitum after the supplement was completely consumed. The trial lasted 14 d with sampling on the last day. Blood plasma samples from each animal were analyzed for plasma urea nitrogen (PUN), glucose, and NEFA concentrations. Morning milk samples were analyzed for protein, fat, lactose, and total solids. Milk fat was extracted and analyzed using the fatty acyl methyl ester (FAME) method. Data were analyzed as a mixed model for a completely randomized design using SAS. Replacing corn and SBM with DDGS did not (P > 0.05) affect total DMI (1.12 ± 0.208 kg), plasma glucose, NEFA, or milk composition but significantly increased (P < 0.05) PUN (20.4 and 15.2 ± 1.31 mg/dL for DDGS and corn plus SBM supplemented does, respectively). The inclusion of DDGS decreased (P < 0.05) the concentration of C12:0 (5.7% and 3.4%), C14:0 (11% and 6%), C16:0 (25.3% and 21.3%), but levels of C18:0 (7.5% and 13.9%), C18:3n6 (0.33% and 0.43%) and C20:1n9 (1.6% and 0.5%) increased. DDGS can replace corn and SBM (59% of diet) over a short feeding period without adverse effects on DMI or milk composition during late lactation. [ABSTRACT FROM AUTHOR]