Collaborative In Vivo Studies on Alfalfa Hay

Chemical composition, digestibility and voluntary intake measures have been obtained for a forage (alfalfa hay) originating from a common source in a collaborative study with sheep and cattle involving 15 laboratories in the United States and Canada. Measures of the variability associated with the chemical and in vivo data have been elaborated for both within- and among-laboratory sources. Major sources of experimental error in this study were found to be due to differences in chemical composition of the forage caused by lack of uniformity of test material, and to differences in the chemical and in vivo methods as used in the collaborating laboratories.