64 FEEDS AND FEEDING 



than the true proteins. Whether these amids can be used for the same 

 purposes in the body as are the proteins of the food, has long been a 

 disputed question. If the mixture of amids in a feeding stuff contains- 

 the proper proportion of the various amino acids (the protein building 

 stones), it now seems certain that these amids can be used the same as the 

 true proteins. 



For example, about one-third of the crude protein in legume hays 

 usually consists of amids. Nevertheless, the crude protein in these feeds 

 is much more efficient for maintenance, growth, or milk production than 

 the crude protein of the cereal grains, which contains but a very small 

 proportion of amids. Similarly, about half the crude protein in corn 

 silage consists of amids, largely formed by the breaking down of proteins 

 in the ensiling processes, for amids form only about 15 per ct. of the 

 crude protein in dried corn fodder. Yet on the dry basis, corn silage 

 is more valuable than corn fodder for stock feeding. 



From these facts it appears logical in making up balanced rations for 

 stock, to base the computations on the total amount of digestible crude 

 protein, as is advocated in the Morrison feeding standards. In view of 

 our present knowledge it seems unwise to ignore entirely the value of the 

 amids as sources of nitrogen for body uses, as is done in the Armsby and 

 Kellner feeding standards. 



III. REQUIREMENTS FOR MINERAL MATTER 



At the present time, the importance of mineral matter for live stock 

 is receiving much popular attention, due chiefly to striking results which 

 have been secured in recent experiments by nutrition experts. As a 

 consequence, many proprietary mineral mixtures are now being widely 

 advertised, often with extravagant claims. It is therefore essential that 

 stockmen understand clearly just how much is known concerning the 

 mineral requirements of live stock. They can then supply any needed 

 mineral supplements for their stock at low expense, without spending 

 unnecessarily large sums on expensive preparations. 



95. Importance of mineral matter. That the mineral matter is of the 

 greatest importance to animals is shown by feeding rations freed as far 

 as possible from it, in which case they die of mineral starvation. Indeed, 

 animals thus fed generally perish sooner than when no food is given. 

 During such starvation the nervous system first suffers in a perceptible 

 manner; marked weakness of the limbs, trembling of the muscles, con- 

 vulsions, and great excitability result. 



Mineral matter is found in all the vital parts of the body. The nuclei 

 of all cells are rich in phosphorus, and the skeleton is composed largely of 

 calcium (lime) combined with phosphorus. Blood deprived of its cal- 

 cium does not clot. The blood serum is rich in common salt and other 

 salts of sodium, while the red blood corpuscles are rich in potassium 

 compounds. The power of the blood to carry oxygen is due to hemo- 



