Effect of Urea Supplementation on the Nutritive Value of NaOH-treated Oat Straw

Abstract

Ground oat straw was treated with a 13.3% NaOH solution (at a rate of 60 liters of solution per 100 kg. straw), neutralized with 16.7 liters of 50% acetic acid, and dried. Untreated or treated straw, each with or without urea (2.5% of ration) and/or sucrose (3.5% of ration) was fed ad libitum to sheep. Alkali treatment resulted in significant increases in energy digestibility, but had no consistent effect on voluntary intake unless urea was also fed. Urea supplementation of treated straw resulted in an average 160% increase in voluntary intake when compared with untreated, unsupplemented controls. Sucrose had no significant effect on either digestibility or voluntary intake. NaOH-treated, urea supplemented straw supplied 220% more digestible energy than the control ration.