Aug. 1, 1925 
Vitamin A in Beef , Pork, and Lamb 
207 
VITAMIN A IN BEEF 
Description of Samples 
The beef, which consisted of the rounds from the carcasses of fat 
steers, was purchased from local packers who slaughter their own 
cattle and from the branch houses of western packers. Two of the 
steers were slaughtered in Chicago, one in St. Louis, one in Omaha, 
and six in Washington, D. C. The rounds were purchased one at a 
time, as needed, and were prepared for use in the feeding tests in the 
following manner. 
A cross section weighing from 20 to 25 pounds was cut from the 
thickest part of the round, the muscle tissue was trimmed free from 
fat and connective tissue, ground, mixed with water and toluol in the 
proportion of 800 grams of meat, 400 c. c. water and 40 c. c. toluol. 
The mixture was spread out in a thin layer in one of the shallow 
pans belonging to the drying oven shown in Plate 1, D and E. The 
oven was filled with five pans of the meat prepared in this manner, 
and the material was dried in a current of air at a temperature that 
did not exceed 60° C. The thin layer of meat became dry on the 
surface in 2 or 3 hours, when it was turned over by means of a spatula 
in order to expose the moist undersurface, and drying was continued 
overnight. The meat was thoroughly dried in from 20 to 24 hours, 
Fig. 2—Vitamin A in beef. Graphs showing rate of .growth of rats that were fed a ration containing 30 per 
cent of dried round steak as the source of vitamin A* in an otherwise adequate diet. The ration was made 
up in parts by weight as follows: Dried round steak No. 869, 30; dried baker’s yeast, 10; ash mixture, 4; 
hardened cottonseed oil, 4.9; cassava starch, 51.1; total, 100 
when it was ground fine and stored in stoppered bottles in the dark 
at a temperature of 34° to 36° F. until needed, the feeding tests being 
begun as promptly as possible. Each lot of dried beef was analyzed 
for nitrogen and fat before being used in a ration. 
Feeding Tests with Beef 
In Figure 2 are shown the growth curves of four rats that were fed a 
ration containing 30 per cent of dried beef No. 869 as the sole source 
of vitamin A in an otherwise adequate diet. The rats grew at a fair 
rate for a time, but growth soon ceased; 3 of the rats developed 
ophthalmia, and one of these had rhinitis also. It is evident that the 
amount of vitamin A supplied by the 30 per cent of dried beef in this 
ration was not nearly sufficient to meet the normal requirements of 
the rats. 
In Figure 3 are shown the growth curves of four rats that were fed a 
ration containing 30 per cent of dried beef No. 874 as the sole source 
of vitamin A. These rats made less satisfactory growth than those 
shown in Figure 2. Three oi the animals developed ophthalmia and 
two died. The amount of vitamin A supplied in this ration was far 
from adequate for the needs of the rats. 
