70 HOW THE ANIMAL USES ITS FEED 



large amounts by young animals. These substances may 

 be supplied by feeding such feeds as alfalfa and clover 

 which are high in lime, and bran and middlings which are 

 high in phosphorus, or feeding ground rock phosphate, bone 

 ash, and calcium phosphate in mineral forms. Charcoal 

 is valuable for hogs and should be supphed to them in a 

 trough mixed with salt. Common salt is a mineral sub- . 

 stance which all animals crave and free access to it should 

 be allowed. 



Young ruminants need roughage. Frequent attempts 

 have been made to raise calves to maturity on purely 

 concentrated rations, but without success. Non-ruminants 

 may grow to maturity on concentrated feeds alone. 



Experiments have proven that milk with a medium 

 amount of fat is better for young animals than milk that 

 is abnormally high in fat. The milk of the average cow 

 has only a medium fat content^ and the calf grows and 

 does well on it. Some of our special dairy breeds have 

 been developed to produce milk rich in fat, but the mineral 

 and protein materials are not correspondingly high, and 

 calves do not thrive so well when fed on such milk. 



Feeding Standards. — It is not long since the feeding 

 of animals was considered little more than the work of a 

 common artisan. Cows, sheep, and horses were either al- 

 lowed to graze the range or were given feeds at hand with- 

 out thought as to their value. At the beginning of the 

 last century, science invaded this field and live stock feed- 

 ing becanie a science as well as an art. In time, standards 

 were formulated setting forth the feed requirements of 

 different classes of animals kept under different conditions. 

 The first standard appeared in 1810, and consisted of a 

 table in which were shown the amounts of different feeding 



