Animal Science, Department of


Date of this Version

January 1998


Published in Nebraska Beef Cattle Report 1998, published by Agricultural Research Division, University of Nebraska Cooperative Extension, and Institute of Agriculture and Natural Resources, University of Nebraska–Lincoln.


Four experiments including vegetative and dormant forages tested modifications of the in situ neutral detergent fiber nitrogen (NDFN) method of estimating forage undegraded intake protein (UIP). Experiments 1, 2 and 3 tested bag size, closure, rinsing, density, and reflux conditions. None of the modifications affected in situ NDFN content. Experiment 4 compared rates of in situ NDFN digestion calculated with or without correction for undegradability. A close relationship exists between rates calculated by the two methods. Modifications make the improved in situ NDFN method a more desirable means of estimating forage UIP than the standard method.