166 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
2. Cleaning the Cows.—The body surface of the cow 
may be soiled with dirt and manure when the animal lies 
down, dust settles on the skin from the air, and dead 
epidermal cells and hair are cast off from the skin. This 
material is very rich in bacteria and, if not removed, some 
of it will be dislodged during milking and may fall into 
the milk pail. The manure contains numerous gas-form- 
ing and putrefactive bacteria and is therefore especially 
objectionable. Dry dirt and manure should be loosened 
with a curry-comb and then brushed out with a stiff brush, 
which will also remove loose hairs and epidermal cells. 
If the dirt or manure is not dry it must be washed off with 
a clean cloth and water. The addition of 1 to 2 per cent. 
of washing soda (a Mason jar lid full to a 12 quart 
bucket) is of great assistance. White hair is likely to 
show a stain after the dirt has been washed off and this 
must not be mistaken for dirt. No dust can be rubbed 
out of an area that is only stained. In cleaning the cows 
special attention should be given to the udder, flanks, 
external surface of the thighs and the switch. In some 
dairies the switch is washed at short intervals. Keeping 
the hair clipped short on these parts and on the buttocks 
will facilitate the work of cleaning. It is advisable to 
have the switch clear the ground by about 4 inches, but 
there is some objection to cutting the switch of pure-bred 
cows. 
After the udder has been brushed dry it should be 
wiped with a damp cloth. The cloth and water should be 
clean at the start and the water should be changed as 
soon as it becomes soiled. Ordinarily, a bucket of clean 
water is required for every eight cows. In high-class 
dairies a small damp towel is used for each cow; each 
towel is used only once and is then washed and sterilized. 
