CHAPTER VI. 
VARIATION OF FAT IN MILK. 
THE percentage of fat in normal milk varies a great deal 
more than any other of the constituents of milk. Dr. Rich- 
mond reports that the fat of milk may go as low as 1.04% and 
as high as 12.52%. Such extreme variations are, of course, 
abnormal. The fat-content seldom falls below 24% or rises 
above 7%. The fat-content of milk from a whole herd of 
cows, varies only within comparatively narrow limits. The 
following are the chief factors which cause the fat-content 
of milk to vary: 
(1) Individuality of cows. 
(2) Breed of cows. 
(3) Time between milkings. 
(4) Manner of milking. 
(5) Whether the milk is fore or after miik. 
(6) Age of cow. 
(7) Lactation period. 
(8) Feed of cows. 
(9) Environmental conditions. 
1. Individuality of Cows.—That the quantity of milk from 
individual cows varies is a fact that is well known to every- 
one who keeps cows, but the average cow-keeper does not very 
well apprehend that the percentage of fat is as variable a factor 
asit really is. Asa rule, when a cow yields only a small quantity 
of milk she is in many instances condemned without taking 
the quality into consideration. If the fat content were taken 
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