Nutrition, Feeding, and Calves: Estimation of Microbial Nitrogen Flow to the Duodenum of Cattle Based on Dry Matter Intake and Diet Composition

摘要

The objectives of this study were: 1) to evaluate the National Research Council equation used to predict microbial N flow to the duodenum in lactating cows, and 2) to determine whether improved equa- tions could be developed by using dietary parameters used in the field. Treatment means from 55 trials with lactating and nonlactating cattle with duodenal cannulas were subjected to the backward elimination procedure of multiple regression. Variation within and among trials was accounted for by weighting the observations and including trial effects in all models.