FIBEX-treated rice straw as a feed ingredient for lactating dairy cows

Treatment of rice straw by the proprietary FIBEX process resulted in increased in vitro digestibility by ruminal microorganisms due to a reduced lag time, increased rate of digestion, increased extent of digestion, and possible removal of inhibitory agents present in untreated rice straw. To determine the value of treated rice straw as a feed ingredient for lactating dairy cows, production parameters and milk composition were determined in a feeding trial with thirteen primparous and six multiparous cows in a switchback design involving two diets and 21 days periods. One diet was a conventional dairy diet that contained alfalfa hay, corn grain, soybean meal (SBM) and several byproduct feeds. The other diet contained these same feed ingredients, but with levels of alfalfa hay, corn grain and SBM that were altered somewhat to provide energy, neutral detergent fiber (35.8%), acid detergent fiber (25.8%) and crude protein (18.0%) levels similar to the treated rice straw added at 7% of dry matter. The diet that contained treated rice straw supported higher neutral detergent fiber intake and milk yield. Milk produced from cows fed the two diets had similar levels of protein, urea nitrogen and lactose. Based on its increased in vitro fermentability at higher fiber content, FIBEX-treated rice straw may be useful as a feed ingredient for lactating dairy cows. (C) 2002 Elsevier Science B.V. All rights reserved.