Milk Stones or Milk Calculi 987 



any milk orifice traversing it will be closed and, if clipped closely, 

 will not show when the animal is grown. When the heifer 

 calves, the rudimentary gland may function temporarily, but 

 soon ceases to secrete because of the pressure of the confined 

 milk. Later the gland atrophies. 



There is a want of power in the teats of some cows to retain 

 the milk within the udder, so that as soon as the gland becomes 

 distended, the milk begins to escape involuntarily through the 

 teat canal. This causes great waste by allowing a large propor- 

 tion of the milk secreted to escape from the teats during the in- 

 terval between milkiugs. Various plans for overcoming the 

 difficulty have been suggested and tried, but none of them are 

 very satisfactory. The cow may be milked very frequently, so 

 as to prevent any great pressure of the fluid within the gland ; 

 or the lumen of the teat canal may be closed by the application 

 of a rubber band or a metal ring. 



Vennerholm suggests the possibility of bringing about a nar- 

 rowing of the teat canal by the excision of a wedge-shaped piece 

 of the teat wall, in the hope that, in healing, the teat orifice may 

 contract sufiiciently to hold the milk. He admits, however, that 

 it is exceedingly difficult to determine the proper amount of tissue 

 to remove. If too much is included, the teat canal may become 

 obliterated or excessively narrowed ; if too little is taken, the 

 object is unaccomplished. Amputation of the apex of the teat 

 may also cause narrowing, but the degree can not be foretold. 



17, Milk Stones or Milk Calculi. 



There are occasionally found, in the udder of the cow, con- 

 cretions of the carbonate of lime, mixed with small proportions 

 of fat or casein, and varying in size from that of a mustard seed 

 to a large bean. They may occur singly or in large numbers. 



When very large they may readily be felt through the walls of 

 the large milk canals or of the cistern, and may become lodged in 

 the teat canal in such a manner as to interfere with the flow of 

 milk, and cause pain to the animal during milking. When 

 occurring in large numbers, they may cause a general sensitive- 

 ness of the gland, accompanied by some stiffness and a 

 straddling gait. 



They are to be differentiated from nodular enlargements in the 

 teats. The latter are immoveable and grow slowly, while the 



