MILK SECRETION. 29 
udder can only be approximately ascertained. The size of 
the udder in some measure indicates this. A cow with a large 
flexible udder is usually a good milker, due to the fact that a 
large udder usually contains a large number of gland-lobules. 
The amount of blood which is turned through the cow’s 
udder to supply the milk-secreting cells may approximately 
be ascertained by the size of the blood vessels. The blood 
enters the udder from the heart near the region of the hips. 
It then passes down through the udder, along the abdomen 
just beneath the skin, until it reaches about midway between 
the flank and the girth. At this place it penetrates the abdom- 
inal wall and enters the thorax. The placc at which the blood 
penetrates the abdominal wall may be felt with the finger. 
It is supposed that the size of this hole is in some measure 
indicative of the milk-producing capacity of the cow. This 
opening in the abdominal wall is called the milk-hole or milk- 
fountain. Large irregular veins are considered a much better 
indication of good milking properties than small straight veins. 
The formation of gland-lobules is entirely inherent in the 
cow. The only way that these may be increased is through 
selection and breeding. The amount of blood which passes 
through the cow’s udder is also largely inherent, although 
this may in a small measure be affected by the amount and 
quality of food given to the cow. It should at all times be 
remembered that a cow is not a mere receptacle into which 
so much food can be introduced, and so much milk drawn 
from the other end. After giving due credit for the influence 
of all other conditions, we must still recognize that the inherent 
conditions affecting the secretion of milk are the most important. 
External Appearance of the Udder.—A cow’s udder should 
be well and symmetrically formed. It should be square, wide, 
extend well along the abdomen of the cow, and back up between 
the thighs. When the udder is empty it should be soft and 
flexible. The teats should be medium large, should be placed 
well apart, and should point downwards. 
There should be little or no depression in the udder between 
