ii4 THE CHEMISTRY OF CATTLE FEEDING 



There can be little doubt that much of the carbohydrate 

 absorbed is directly oxidised in the blood. These compounds 

 suffer oxidation more readily than any other constituent of 

 the food, and it is only when they are present in excess, i.e. 

 when there is more than can be oxidised, that any can be 

 stored up as body fat. The fat of the food is probably not 

 oxidised until all, or nearly all, the carbohydrates have been 

 disposed of. In other words, the carbohydrates protect the 

 fat from oxidation ; but if there be not enough carbohydrate 

 to do this, then some of the fat also is oxidised, and it is only 

 the excess that can be stored up as body fat. 



It may be said, therefore, that it is from the excess of 

 non-nitrogenous nutrients fat and carbohydrates taken 

 together that body fat is formed, and then only if there 

 is excess of these ingredients over and above what naturally 

 suffers oxidation. Under these conditions, i.e. in the presence 

 of excess of fat and carbohydrates, the oxidation of protein 

 is reduced to a minimum. It is protected by the non- 

 nitrogenous nutrients. But if the fat and carbohydrates are, 

 together, insufficient to protect it, increased oxidation of 

 protein follows immediately. If the food absorbed contain 

 more protein, fat, and carbohydrates than are oxidised in the 

 blood, the excess may be used to repair the waste of tissue, 

 and can be stored up in the body. Protein, of course, is only 

 formed from nitrogenous matter, but body fat may be formed 

 from all or any of the constituents, if the protein, fat, and 

 carbohydrates are together not equal to what is naturally 

 oxidised, the waste cannot be repaired and the animal loses 

 weight. 



