Performance of dairy cows fed concentrates differing in their contents of easily fermentable carbohydrates, with roughage fed either ad lib. or at a restricted rate

Abstract

In a trial following a two-factorial (2×2) design, 4 groups of 19 multiparous dairy cows were fed concentrates containing per kg either 452 or 202 g starch + sugar. Grass silage and maize silage (70:30, on dry matter basis) were fed either ad lib. or at a restricted rate of 8.5 kg per cow per day. Roughage was given group-wise in 3 meals per day, concentrates were supplied individually according to actual milk yields. During the first 200 days of lactation, average daily intakes of concentrates exceeded 9 kg dry matter per cow in each experimental group.No significant feeding effects on amounts of milk or milk fat were found. Cows fed the starchy concentrates produced significantly more protein than cows fed the fibrous concentrates. Feeding roughage ad lib. results in higher live weights of the cows with no significant effect on production of milk, fat or protein. No dietary effect on the health status of the cows was found.