80 JUDGING CATTLE 



making milk, which is the dairy cow's specialty. With the 

 exception of the water, the udder is generally considered to 

 produce as the direct product of its own action all the constit- 

 uents of the milk. The casein, the fat and the milk sugar 

 are elaborated in the udder, the only constituent that is 

 thought not to undergo any change is the water in the blood. 

 However, it is from the blood that the milk is made, for the 

 action of the udder is to so change all the constituents that 

 the milk distinctly becomes the peculiar product of the 

 udder. 



To better understand the construction of the udder let us 

 follow the course of the small opening which exists at the 

 end of the teat. This opening at the upper part of the teat 

 swells into a cistern or milk reservoir, where the milk 

 accumulates to a degree between the time of milking. The 

 milk is prevented from passing out of this cistern through 

 che teat by a small muscle (sphincter) which holds the milk 

 in the udder until relaxed by the stimulation of milking. 

 From this cistern a canal extends further into the udder. 

 This branches many times and at the end of each branch 

 there is a cluster (a lobe) of tissue very similar to a bunch 

 of grapes. What is known as the lobe is similar to the 

 bunch, the lobule resembling one grape, and what is known 

 as the alveoli the seeds of the grape. The alveoli are lined 

 with small cells in which the milk is made. These cells 

 produce within themselves the fat peculiar to milk and also 

 secrete the water, salts, etc. , that enter into the composition 

 of milk. The milk being secreted in these millions of small 

 cells, which compose the udder, passes into the branches that 

 lead to them, and from these it passes into the main branch 

 and finally reaches the milk cistern, where it accumulates 

 until milking begins. The four quarters which make up the 

 whole udder are each constructed in the way indicated and 

 they act somewhat independently of each other. 



