Effects of a diet containing dried grape pomace on blood metabolites and milk composition of dairy cows.

The effect of a diet containing 15% grape pomace (GP) on the general health status and milk quality of dairy cows was assessed by plasma biochemistry and total polyphenol (TP) content, milk polyphenols, milk composition and milk protein fractions. Among the polyphenols measured by liquid chromatography-mass spectroscopy in GP, in feed containing GP (GP+) or not containing GP (GP-), gallic acid and epicatechin were present in the highest concentrations (67.58 and 19.23 µg mL Inclusion of 15% GP in the diets of dairy cows is beneficial for overall normal blood constituent metabolism and helps to maintain cow health. The milk of cows fed with a GP diet preserves the normal levels of fat, protein and caseins, and has increased levels of components that make this milk a versatile ingredient material for the food industry (e.g. model whey powders, stability of lactose-rich powders). © 2016 Society of Chemical Industry.