268 THE BREEDING OF ANIMALS 



apart from its digestible protein content and calorific 

 value, is positive." 



254. The permanent effect of retarded growth. Is 

 the retardation of growth resulting from unfavorable 

 environment a permanent condition? Is it possible per- 

 manently to stunt an animal? This question is one of 

 great interest to the practical breeder of live-stock and 

 the live-stock farmer. The animal is often employed by 

 the farmer for the purpose of disposing profitably of food 

 materials which are of limited value from the standpoint 

 of nutrients and digestibility, but nevertheless have a 

 food value. Teachers and investigators in animal hus- 

 bandry have for a long time taught that any condition 

 which resulted in stunting the young animal, perma- 

 nently affected the mature individual. It has also been 

 claimed by some that the capacity to grow was materially 

 diminished by a stunting period. 



The history of two animals which were fed at the 

 Missouri Experiment Station by P. F. Trowbridge 1 is of 

 great interest in attempting to answer this question. One 

 of these animals was given a full ration from birth and 

 the other animal was given a so-called maintenance ration 

 from three months of age to thirteen months. The use 

 of the term maintenance ration in this connection means 

 that it was planned to feed the animal sufficient food to 

 cause it to maintain a uniform body weight. As a matter 

 of fact, the animal added somewhat to his total weight 

 in the ten months of stunting. The tables and pictures 

 (Plate XXV) give a very clear idea of the general results 

 of this trial. The full-fed animal gained rapidly and at 

 the end of fourteen months weighed 956 pounds. The 

 young animal fed merely a maintenance ration weighed 



1 Missouri Experiment Station, unpublished data. 



