24 PRINCIPLES OF FEEDING FARM ANIMALS 
ties in which the lipoids occur in the animal body, they appear to be 
of the greatest importance in the nutrition of animals, especially 
in the case of growing animals. 
Ash Materials.—The animal body contains the same ash ma- 
terials as are found in plants, and it holds true, as a general proposi- 
tion, that the elements which are essential to the life of plants are 
also essential to animal life. In the case of two elements, sodium 
and chlorin, the evidence at hand is not sufficient to show that 
they are absolutely essential to plants, but, since they are present 
in all soils, plants always contain an ample supply of both elements. 
It is definitely known, however, that both sodium and chlorin are 
essential to the growth of animals and to the continued exercise 
of their vital functions: We shall see that gastric juice, one of the 
digestive fluids of the body, contains free hydrochloric acid; this 
acid comes from the sodium chloride (common salt) found in the 
feed of the animals or eaten directly by them. Animals fed largely 
coarse feeds receive a sufficient amount of salt in the feed to supply 
their wants, but when fed much grain or other concentrates low in 
mineral matter, they need more salt than that contained in the 
feed; all farm animals relish salt greatly, and the practice ‘of 
“salting ” livestock has, therefore, become quite general. 
Salt improves the appetite of the animals and increases the flow 
of digestive juices; it promotes and regulates digestion and should, 
therefore, be furnished in ample amounts. In the case of milch 
cows at least, a supply of salt in addition to that in the feed is 
essential to their continued health, both because of their large feed 
consumption, especially grain feed, and because of the amount of 
chlorin that is daily removed in the milk. The general practice 
among dairy farmers is to supply about an ounce of salt daily per 
cow, placing it before them in the mangers or giving them access 
to salt in the yard. Unless milch cows have access to salt, abnormal 
conditions will soon appear which will result in a general break- 
down after a period varying with different cows from a month to 
more than a year. The gradual reduction in vitality of the animals 
which is brought about by a lack of salt, as shown by Babcock, is 
evidenced by “loss of appetite, a generally haggard appearance, 
lusterless eye, a rough coat, and a very rapid decline in both 
weight and yield of milk.” ? 
Phosphate of Lime——The mineral components present in the 
animal body in the largest quantities are lime and phosphoric acid. 
They make up the skeleton of the body and form about 80 per 
2 Wisconsin Report 22, p. 154. 
