346 AGRICUI/TURAI, CHEMISTRY 



exceed and in others fall short of the standards given. 

 On this account, it is not possible to adhere too closely to 

 fixed rules in the rational feeding of farm animals. 

 When foods containing the largest amounts of nutrients 

 are produced and so fed as to secure the highest degree 

 of digestibility, smaller amounts are required than when 

 foods low in available nutrients are used and injudiciously 

 fed. 



471. Food Supply at Different Stages of Growth. 

 The amount and nature of the food consumed should vary 

 with the period of growth. Rations for young and grow- 

 ing animals should contain a larger amount of protein 

 and a smaller amount of non-nitrogenous compounds 

 than rations for mature animals. This is because more 

 food is required for building purposes in the early stages 

 of growth, than in later stages when more is required 

 for heat and energy. These facts may be observed from 

 the table of feeding standards. For example, a calf 

 three months old and weighing 150 pounds requires per 

 day 0.6 pound digestible protein and 2.4 pounds diges- 

 tible non-nitrogenous compounds. When the animal is 

 a year old and weighs 500 pounds, it requires 1.3 pounds 

 of digestible protein and 6.9 pounds of digestible non- 

 nitrogenous compounds. The animal has increased in 

 weight more than three times while the increased demand 

 for digestible protein is only about twice as great, but 

 for the non-nitrogenous compounds four and one-half 

 times as great. 



When an excessive amount of starchy and non-nitro- 

 genous foods is fed to a young and growing animal, 



