Quality of Milk from Lactating Dairy Cattle Fed Dried Distillers Grains with Solubles

Abstract

Healthy mid-lactation Holstein dairy cows (n=24) were fed total mixed rations containing dried distillers grains with solubles (DDGS). The objective of this study was to examine the effect of feeding DDGS to lactating dairy cows on production parameters and flavor and oxidative stability of milk. Cows were assigned to two groups and fed one of three treatment diets (0% DDGS, 10% DDGS, 25% DDGS by dry matter (DM)) as a total mixed ration. Each group was fed all three of the diets after a wash-out period of 7 days. Milk yield was unaffected by both the 0% and 10% DDGS diets but decreased significantly when fed the 25% DDGS diet. Rumen volatile fatty acids were unaffected by treatment. Milk protein and solids-not-fat (SNF) increased with increasing inclusion of DDGS, but milk fat decreased concomitantly. Milk fatty acid composition was affected with milk fat from cows fed higher concentrations of DDGS producing milk with higher concentrations of unsaturated fatty acids. Milk oxidative stability was unaffected by dietary treatment, and milk flavor, as determined by a trained sensory panel, also was unaffected. The results of this study indicate that feeding of DDGS to lactating dairy cows, under controlled conditions, does not have negative effects on milk oxidative stability or flavor; however, feeding 25% DDGS did negatively impact milk production and changed milk fatty acid profile.