38 Milk and Its Products 
to four weeks before calving, than though she is 
milked right up to calving, as often may be done. 
So far as can be ascertained, the good effect of this 
dry period is very largely physiological, the secreting 
glands in the udder are stimulated to greater activity 
by reason of having been inactive for a short space. 
While dairymen often speak of this period of dryness 
as a resting period, its good effect is probably not 
so much due to the resting of the general vital 
powers of the animal as to the physiological con- 
dition of the udder itself. 
In most cows when the period of pregnancy has 
reached about the seventh month, there is a marked 
diminution in the flow of milk, and the udder shrinks 
rapidly in size. If now regular milking ceases, the 
cow soon “dries up,” the udder shrinks away and 
becomes flaccid and empty, except for a small amount 
of watery saline fluid. About two weeks before par- 
turition, the udder begins to take on renewed activity. 
It increases rapidly in size, but remains soft and spongy 
under normal conditions until a very short time 
before calving. If the cow is very fat, if she is 
fed heavily on stimulating, heating foods, or if there 
are other conditions that tend to plethora of the body, 
the swelling of the udder may be unduly large, take 
on an inflammatory character, and the udder becomes 
eaked. In cows of a heavy milking habit this often 
is a very serious condition, and: may even destroy 
the usefulness of the animal, or at least one or more 
quarters of the udder. It is obviated by taking care 
that the animal is fed only loosening and cooling 
