82 Report oF DEPARTMENT OF ANIMAL HUSBANDRY OF THB 
food, and later those containing larger and increasing proportions 
of grain foods. 
INTRODUCTION. 
In earlier experiments it was found that rations containing 
animal food gave better results than those consisting largely or 
altogether of grain food. With abundance of green forage and 
grit the result was the same. The more common grain foods 
contain more crude fiber and generally less nitrogenous matter, 
fat and mineral matter than the animal foods, and in ordinary 
rations disadvantage might come from undue proportions of 
these constituents. But when, by using an unusual number of 
foods, palatable rations were made to contain nearly equal pro- 
portions of these constituents, the advantage was still decidedly 
in favor of those containing animal food. 
With chicks this advantage did not appear when care was 
taken to supply abundant mineral matter to the vegetable food 
ration. But with ducklings a ration entirely of vegetable origin 
always proved inferior; and it seems necessary with all except 
costly or very unusual feeding materials, to use considerable 
animal food for satisfactory results. In most of the feeding 
experiments referred to, from 35 to 40 per ct. of the protein in 
the efficient rations was derived from this source. 
To learn how much animal food in the prepared commercial 
forms could be used without disadvantage, and what proportion 
it is ordinarily desirable to use, supplementary feeding trials 
were made. Results from some of these are herein reported. 
No injury to the health of ducklings appeared at any time 
when different animal foods were moderately or quite freely used, 
even under a liberal feeding at one time of some animal meal 
that could not be fed to young chicks without disastrous results. 
FIRST FEEDING TRIAL. 
CONDITIONS. 
Records from the feeding of two lots of ducklings of different 
uges on rations in which over nine-tenths of the dry matter and 
about 98 per ct. of the protein were derived from animal 
products follow in tabulated form. Sand was regularly added 
to the food, but nothing else except green alfalfa was fed besides 
