Production of dairy cows fed distillers dried grains with solubles in low- and high-forage diets

Authors: RANATHUNGA, SANJEEWA - South Dakota State University; Kalscheur, Kenneth; ANDERSON, JILL - South Dakota State University; HERRICK, KEVIN - South Dakota State University

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2018
Publication Date: 12/1/2018
Citation: Ranathunga, S.D., Kalscheur, K., Anderson, J.L., Herrick, K.J. 2018. Production of dairy cows fed distillers dried grains with solubles in low- and high-forage diets. Journal of Dairy Science. 101(12):10886-10898. https://doi.org/10.3168/jds.2017-14258.
DOI: https://doi.org/10.3168/jds.2017-14258

Interpretive Summary: Incorporation of corn dried distillers grains with solubles (DDGS) in lactating dairy cow diets has become a common feeding practice in the United States. It can be used as an alternative protein supplement to soybean meal or as an alternative energy source to corn because of its undegradable protein, digestible fiber, and fat concentration. The major concern with feeding a greater amount of DDGS is that there is a possibility of causing decreased milk fat concentration. While no single factor may be responsible for decreased milk fat concentration, interactions of several dietary factors (including higher amounts of digestible carbohydrates, inadequate effective fiber, and a greater concentration of polyunsaturated fatty acids) could lead to milk fat reduction. The objective of this study was to investigate the effect of adding dried distillers grains with solubles at 0 or 18% (dry matter [DM] basis) into diets formulated with low (41% DM basis) or high (60% DM basis) forage concentrations. Results demonstrated that forage concentration in the diet influences performance of cows, but not the addition of DDGS. This study demonstrates to dairy producers and nutritionists that inclusion of DDGS at 18% (DM basis) of the diet with a higher forage concentration (60% DM basis) in the lactating dairy cow diets could reduce feed costs, maintain greater milk production, and prevent negative effects associated with feeding DDGS, such as decreased milk fat concentration or milk fat depression.

Technical Abstract: The objective of the study was to investigate the effects of dietary forage and distillers dried grains with solubles (DDGS) concentration on the performance of lactating dairy cows. Twelve Holstein cows were blocked by parity and milk production and assigned to replicated 4 × 4 Latin squares with a 2 × 2 factorial arrangement of treatments. Diets were formulated to contain low forage [LF; 17% forage neutral detergent fiber (NDF)] or high forage (HF; 24.5% forage NDF) and DDGS at 0 or 18% of diet dry matter. The forage portion of the diet consisted of 80% corn silage and 20% alfalfa hay (dry matter basis). A portion of the ground corn and all of the expeller soybean meal and extruded soybeans from 0% DDGS diets were replaced with DDGS to formulate 18% DDGS diets. Overall, we found no interactions of forage × DDGS concentrations for any of the production measures. We observed no effect of diet on dry matter intake. Milk yield was greater when cows were fed LF diets compared with HF diets (43.3 vs. 41.5 kg/d). Milk fat concentration (3.03 vs. 3.38%) was lower for cows fed LF diets compared with HF diets, whereas protein concentration (3.11 vs. 2.98%) and yield (1.34 vs. 1.24 kg/d) were greater for cows fed LF diets compared with HF diets. Yields of fat, total solids, energy-corrected milk, and feed efficiency were not affected by diets. Cows partitioned energy equally for milk, maintenance, and body reserves. Replacing starch from ground corn and protein from soybean feeds with DDGS at either 17 or 24.5% of forage NDF concentration in the diet was cost-effective and did not affect the production performance of lactating dairy cows.