74 BUTTER-MAKING. 
and they are drawn out only when the last milk is removed. 
(3) The fore-milk has been subjected to a re-absorption process 
of the lymphatics. The third factor perhaps plays only a 
small part in reducing the fat-content of the fore-milk. As 
the fore-milk contains so very little fat, and a great many 
micro-organisms, it is often advantageous to reject the first 
few streams of milk. Especially is this important when sani- 
tary milk is desired. 
It is in many instances customary, in order to apportion 
the calf a certain amount of milk, to first partly milk the cow 
by hand, and send this milk to the creamery, and then allow 
the calf to suck the remainder. The results of such procedure 
are plain, yet it is practiced to a large extent. When dis- 
covered, it has in many instances explained why a certain 
creamery patron’s milk has been testing low at the creamery. 
Age of Cow.—There is a time during the life of a cow when 
she is most vigorous and most productive. At the time she 
first calves (about three years old) the cow or heifer is. still 
growing, and her milk-producing capacity is not so great then 
as it is later on, when she becomes matured. After this increase 
in quantity there is also a slight increase in quality. At the 
age of about seven years the cow is usually at her best. As 
the cow advances in age, usually the quantity and quality 
diminish. However, the individuality of cows prevents draw- 
ing any definite lire. In some cows age has considerable 
effect, while in others age has but little effect. 
Lactation Period.—By lactation period we understand the 
milking period, from the time of calving until the cow is dried 
up. The first few days after calving, the cow yields milk 
which is rich in solids, not fat. The fat-content in milk from 
most cows usually increases a trifle during the first two weeks 
after parturition. Then, when conditions are normal and uni- 
form, the percentage of fat is nearly constant for about three 
months. After this time the quantity decreases and the 
quality gradually increases a trifle. This applies more fully 
if the cow is pregnant. Most cows calve in the spring of the 
