38 BULLETIN 769, U. S. DEPARTMENT OF AGRICULTURE. 
BUTTER AND CHEESE. 
AMOUNT OF PAT AVAILABLE IX THE FORM OF DAIRY PRODUCTS. 
Of all the fats and oils, the one most universally and extensively 
produced is milk fat, in its various forms of butter, cheese, and their 
modifications. No exact figures for the total production are available, 
but it is estimated that from 1,630,000,000 to 2,000,000,000 pounds 
are produced annually. The lower figure represents about 40 per 
cent of the entire milk production, which, based upon an average of 
3.716 pounds of milk from each of our 22,768,000 dairy cows, is 
84,605,888,000 pounds. In other words, since it takes 21 pounds 
of milk to make 1 pound of butter, it is necessary to churn 34,650,- 
000,000 pounds of milk to form 1,650,000,000 pounds of butter. 
We must not lose sight of the fact, however, that this butter is not all 
fat. the legal requirements being that butter shall contain less than 
16 per cent of water. The actual fat in all the butter produced 
annually in the United States is between 1,300,000,000 and 1,400,000,- 
000 pounds. 
The fat which occurs in cheese is practically identical with that in 
butter. Since we produced in 1917 about 476,000,000 pounds of 
cheese, containing on an average 35 per cent of fat, it is perhaps no 
more than common justice to our good friend the cow to credit her 
with an average annual production of an additional 166,000,000 
pounds of butter fat. To give the dairy industry full allowance for 
its share in supplying the Nation with fats, attention should also be 
directed to the fact that the 1,416,000,000 pounds of butter fat 
which in 1917 went into our butter and cheese constituted only 50 
per cent of the^total milk produced. Thus it is seen that from this 
industry we have in one year derived over 2,832,000,000 pounds of 
one of the very best food fats known to man. 
The Department of Commerce figures show that the exports of 
butter from the United States have increased very rapidly during the 
past six years, and that the foreign demand for this product in 1917 
greatly exceeded the average for the first three years of the war. 
This can be accounted for by the fact that England and France 
formerly depended to a great extent upon Holland, Belgium, and 
Switzerland for their supply of butter and cheese. 
FISH OILS. 
PRODUCTION AND USES. 
Although our fish oil industry may be said to occupy a minor 
position in the general oil market, the approximately 30,000,000 
pounds which we produce annually, and the 20,000,000 pounds 
which we import, make fish oil worthy of some consideration. Our 
imports of fish oil, including cod and cod liver oils, were about 5 per 
