Under the conditions of these experiments, dehydrated comfrey was not a suitable ingredient for a laboratory rat ration at the 20% level, where it supplied half of the protein, and it was completely unsatisfactory at the 40% level. The swine digestion trial indicated that the comfrey used had a dry matter content of 12.1% digestible crude protein, and 52.7% TDN content. The ratings for crude protein, total digestible nutrient content and nitrogenfree extract were all lower for comfrey than for the control ration.

Milton D. Miller, Extension Agronomist, supplied the dehydrated comfrey and assistance was received from James T. Elings, Extension Animal Scientist, and Bob D. Wilson, summer working student who assisted with the rat trial.