Wheat Straw-Urea Diets for Beef Steers: Alkali Treatment and Supplementation with Protein, Monensin and a Feed Intake Stimulant

Abstract

Summary Diets of wheat straw, urea and minerals were fed to growing steers in two 105-day feeding trials and to rumen-fistulated steers in two short-term changeover trials to evaluate the effects of alkali treatment, fine grinding and pelleting, and supplementation with small amounts of protein, a chemical feed intake stimulant (elfazepam5) and monensin5. In experiment 1, alkali (A) treatment (4 kg NaOH/100 kg straw) increased apparent organic matter digestibility in coarsely ground straw (C) (54 vs 69%, P.05). On straw supplemented with urea and minerals, intake and weight gain of growing steers ranged from 1.6% of body weight and .09 kg/day for C straw to 2.5% of body weight and .61 kg/day for AP straw. In samples taken 3 hr after feeding, rumen ammonia levels were lower (31.4 vs 20.9 mg N/100 ml, P .01) between diets; however, the rumen retention time of undigested particles was reduced from 44 to 35 hr (P