School of Agriculture, University of Nottingham, Sutton Bonington, Loughborough, Leics., LE12 5RD, England
2Present address: Department of Animal Science, Punjab Agricultural University, Ludhiana-141004, India.
3Present address : Group Development Manager, George Worrell and Sons Ltd., 46-50 East Parade, Harrogate Yorks., England.
1Part of the thesis approved by the University of Nottingham for the award of Ph.D. degree.
Utilization of nitrogen from throe promising slow-release urea derivatives, viz. etude monomethylol-urea (MMU-I), purified raonomethylol-urea (MMU-H) and isobutylidene-dlurea (IBDU) were compared with SBM and urea in a barley based ration fed to sheep. The level of substitution was equivalent to 2% urea. Daily nitrogen intake was 31+0.5 g. The DM digestibility was minimum (76.5% I with MMU-I diett Purification of MMU from 20% N content to 22.4% N content improved both DM digestibility and N retention. Fractionation of faecal N revealed that 0.6, 9.2 and 23.9% of 1BDU, MMU-H and MMU-I, respectively were not digested. Maximum of absorbed N was retained with MMU-H (25.4%) followed by IBDU (25.0%), SBM (23.0%), MMU-I (22.2%) and urea (21.0%). The BV of 50, 47, 46, 45 and 39 for MMU-H, IBDU, MMU-I, SBM and urea diets were recorded, respectively. Among the slow-release urea derivatives MMU-II proved a better NPN source.
