336 NUTRITION OF FARM ANIMALS 



of the body cells and to the important part played by the ash 

 ingredients in maintaining this neutrality. 



a. Acidosis. A variety of chemical processes, both normal 

 and pathological, occur in the body which tend to disturb its 

 neutrality either by the addition of acid or the giving off of 

 alkali so as to produce the condition known as acidosis, by 

 which is meant a relative excess of acid over basic radicles. 



A well-known example of pathological acidosis is that observed in 

 diabetes. The perverted metabolism of this disease results in the 

 production of large amounts of oxybutyric acid (266), which is neu- 

 tralized to a certain extent by means of ammonia derived from the 

 katabolism of protein but whose gradual accumulation finally results 

 in the diabetic coma. Another example is the form of infantile aci- 

 dosis in which an excess of fat in the food results in the formation of 

 insoluble calcium salts of the fatty acids in the intestines and so re- 

 moves basic ingredients in the feces. It has been suggested that the 

 failure of young animals to thrive on milk exceptionally rich in fat 

 may be due in part to the same cause. 



Several sources of acid exist in the normal organism. 



First, acids may be consumed as such, either in natural 

 products or in fermented materials like silage. These acids 

 are neutralized by the alkalies of the saliva or of the pancreatic 

 juice, which are thus temporarily withdrawn from the body 

 fluids. After resorption, however, the resulting alkali salts of 

 the more common acids are readily oxidized, yielding carbon 

 dioxid and water and restoring to the body fluids the bases 

 previously withdrawn. Small amounts of some acids, such as 

 tartaric and malic, however, tend to escape oxidization and to be 

 excreted in the urine, carrying a corresponding amount of base 

 with them. Oxalic acid and its salts are oxidized with difficulty 

 and tend to impoverish the body in calcium by the formation 

 of the insoluble calcium oxalate. This acid is liable to be es- 

 pecially injurious to horses and swine and to young ruminants, 

 while in mature ruminants it seems to be largely destroyed by 

 fermentation in the first stomach. 



Second, the fermentations in the paunch of ruminants are a 

 source of large amounts of organic acids which, like those con- 

 tained in the feed, may cause a temporary withdrawal from the 

 body fluids of alkali which is later restored when the salts are 

 katabolized. 



