12 BULLETIN 1413, U. S. DEPARTMENT OF AGRICULTURE 
In these trials it was found that the cows readily ate a con- 
centrate ration containing up to 1.18 pounds of cocoa meal per 
cow, per day, " with no apparent ill effect on their physical well- 
being." The feeding of cocoa to the extent of 20 per cent of the 
grain ration reduced the milk flow by as much as 13 per cent, but 
tended to increase the percentage of butt erf at in the milk. One 
cow, a 476-pound Jersey heifer, is stated to have received a liberal 
grain ration containing up to 40 per cent of cocoa meal (averaging 
1.75 pounds of the cocoa per day) for five and one-half months. 
During this period she gained 100 pounds, but her milk yield was 
greatly decreased. Several full-grown cows received as much as 
2.2 pounds of cocoa meal per day each for periods of from one to 
three days. No mention is made of any untoward physiological 
symptoms that might be referable to theobromine, nor is the pres- 
ence of this drug in the cocoa meal discussed. 
Notwithstanding this apparent tolerance of cocoa by neat cattle, 
on the whole it must be concluded that caution should be observed 
in feeding cocoa products to animals. It can hardly be questioned 
that the quantity of cocoa that can be fed daily is limited; and, judg- 
ing by reports of past experiences with the feeding of cacao shells, 
certain animals, notably horses, are especially susceptible to the poi- 
sonous action of theobromine. 17 
The extraction and preparation of theobromine commercially 
from cocoa cake does not appear to have been described in textbooks 
on the cocoa industry. Knapp (26), however, mentions a process 
patented by de Grousseau and Vicongne for the preparation of 
theobromine from cacao waste (18). 
Utilization of by-product or surplus cocoa cake as fertilizer mate- 
rial has not previously received scientific consideration, a search of 
the literature reveals. Apparently not even laboratory investigation 
of the fertilizer possibilities of the product has ever been made. 
Though a few representatives of the fertilizer trade are familiar 
with the amounts of total " ammonia " and potash present in the 
cakes and extracted cocoa, no information appears to have been pub- 
lished or made available on the solubility or quality of the ammonia 
or on the range in fat content. Neither has the theobromine content 
and general nature of the extracted cocoa been investigated. It was 
deemed necessary, therefore, to obtain authentic samples of the dif- 
ferent types of cocoa by-products and to undertake a laboratory 
study of their chemical composition and nature. 
PRESENT INVESTIGATION 
Samples representative of the by-product cocoa cake and of the 
solvent-extracted cocoa being produced in the United States were 
requested from manufacturers. Eighteen samples were obtained, of 
which 12 were hydraulically pressed cake and 4 represented defatted 
cocoas that had been subjected to solvent extraction. One of the 
cakes was made by pressing ground whole beans, including shells 
and germs. Two samples of commercial cacao shells also were 
obtained. Five producers of by-product press cake and the one firm 
17 One producer of the by-product cake stated that his attention had been called to a 
case in which the- death of a number of hogs was attributed to feeding them cocoa meal, 
