208 DESCRIPTION OF FEEDING STUFFS: 
Buttermilk is the by-product obtained in the manufacture of 
butter. It is used especially as a feed for growing and fattening 
pigs. It contains, on the average, somewhat less than 10 per cent 
solids, viz., 0.5 per cent fat, 4 per cent casein and albumen, 4.4 per 
cent milk-sugar, and 0.7 per cent ash. It does not, therefore, differ 
materially from skim milk in composition, and extensive com- 
parative feeding experiments conducted by the Copenhagen station 
and elsewhere have shown that buttermilk is very nearly of the 
same value as skim milk for feeding pigs. It can also be fed to 
calves with good results, if special care is taken to feed it in fresh 
condition and in small amounts at the start, so as to gradually 
Fic. 39.—Holstein skim-milk calves—promising stock for the dairy herd. 
accustom the stomach of the young animals to it. Unless it can 
be fed in the manner suggested and with the most scrupulous 
cleanliness, the attempt had better not be made to feed buttermilk 
to calves, as disastrous results are likely to follow. 
Whey is obtained as a by-product at cheese factories, and is 
supplied to patrons in large quantities. It contains only about 
6.6 per cent solids, viz., 0.3 per cent fat, 0.85 per cent albumen 
(with a little casein in suspension), 4.8 per cent milk-sugar, and 
0.65 per cent ash. Whey is a more dilute and more carbonaceous 
feed than either skim milk or buttermilk (nutritive ratio, 1:9, 
against about 1: 1.5 for skim milk and buttermilk) ; hence it may 
be better supplemented by protein feeds than these, like wheat 
bran, small grains, and oil meal. Whey is fed to pigs almost en- 
