CHAPTER VI. 

 THE MILK GLANDS AND THEIR FUNCTIONS. 



The milk glands are essential to the proper perform- 

 ance of the reproductive function. Man has however 

 made use of the milk function and developed it to such 

 an extent that some cows are now specialists in milk pro- 

 production; the result of such specialization is that the 

 milk glands have become larger, the milking habit more 

 persistent, the quantity given greater and the liability 

 to disease increased. 



The Udder. The arrangement and construction of these 

 milk gland varies in the different animals. The mare's 

 udder consists of two halves each presenting a nipple or 

 teat pierced by openings for the passage of milk; in mares 

 that have never borne young the teats and udder are 

 small, in old brood mares the udder and teats are large 

 and flabby. 



The udder of the cow is composed of two halves, each 

 again divided so that we speak of the quarters of an 

 udder; while in the ewe two glands only are present, each 

 with a teat; in the sow the udder extends along the belly 

 and has from eight to ten teats belonging to as many 

 glands, arranged in two rows lengthwise. The interior 

 of the gland is made up of gland tissue formed into lobes, 

 each lobe being made up of smaller lobules, each of these 

 in turn being made up of cells and small ducts. These 

 ducts unite to form larger ducts, all of which gradually 



