GROWTH AND FATTENING 73 



the process is repeated during several generations, the effects will be- 

 come marked and permanently injurious. The practical lesson is 

 taught that young animals should be fed a combination of feeding 

 stuffs that will allow normal growth. This calls for a ration con- 

 taining crude protein and mineral matter not only in ample amount, 

 but also of suitable composition for the rapid formation of body tis- 

 sues. When growth is completed, the food supply may then consist 

 largely of carbohydrates and fat, which are the cheap and abundant 

 sources of animal fat. 



Growth under adverse conditions. — Extensive experiments carried 

 on at the Missouri and Kansas 10 Stations are of much interest in 

 showing what happens when young animals are fed only enough feed 

 to maintain their weights. Due to the impulse toward growth, young 

 steers fed scanty rations continued to grow in height, tho not gaining 

 in weight. In this effort the fat stored in the body was withdrawn 

 and used up as body fuel, the animals becoming thin in flesh as the 

 scanty feeding progressed. 



For 70 to 120 days, depending on how vigorous they were and how 

 much fat they carried, young steers fed only enough to maintain their 

 weight gained as rapidly in height as others on full feed. After this 

 period the increase in height became less rapid, ceasing altogether in 

 from 6 months to a year and half, by which time the animals had be- 

 come quite thin and had burned up all the fat in their bodies which 

 was not absolutely necessary to life. Growth on scanty rations is not 

 due directly to the fat re-absorbed from the body. The animal burns 

 its stored fat to support the body, and the scanty protein supply in its 

 food is used for building body tissue. 



As a result of these studies Waters of the Kansas Station points 

 out that a young animal may reach normal size by any or all of the 

 following ways : 



1. By growing steadily from birth to maturity. 



2. By storing fat during a period of abundant food supply, which 

 will help to tide over a limited period of sparse food supply without 

 serious checking of growth. 



3. By prolonging the growth period. 



4. By an increase in the rate of growth during a period of liberal 

 feeding following a period of scanty feeding and low gain. 



5. By using its food more efficiently. Apparently when an animal 

 is kept for a long period on scanty food, it gets on a more economical 

 basis than when liberally fed. A ration which is at first insufficient 



o Waters and Trowbridge, Proc. Prom. Agr. Sci. 1908; information to the 

 authors. 



io Waters, Cochel, and Vestal, Kansas Industrialist, May 10, 1913; Apr. IS, 

 1914; and information to the authors. 



