60 RURAL VETERINARY SECRETS 



THE MILK GLANDS AND THEIR FUNCTIONS 



The milk glands are essential to the proper performance of the 

 reproductive function. Man has, however, made use of the milk func- 

 tions and developed it to such an extent that some cows are now 

 specialists in milk 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 glands 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 di- 

 vided 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 large ducts, 

 all of which gradually converge to the center of the gland where 

 they form cavities known as milk sinuses, (they used to be termed 

 lactiferous (milk-making) sinuses. 



The milk sinuses empty the lacteal secretion into the teats, 

 each of which is guarded by a sphincter muscle at its lower end. 

 It is this sphincter muscle which is so hard to relax in some cows 

 that causes them to be termed hard milkers. The udder is lined 

 with a delicate cell structure known as epithelium, this cell structure 

 extends to the alveoli (lobules). 



SHAPE OF MILK GLAND 



It has been stated that the internal parts of the udder consist 

 of cells and other structures; and as such, require the use of the 

 microscope more or less in their examination. Besides the cells, 

 consideral)le connective tissue enters into the udder formation and 



