THE FEED REQUIREMENTS OF FARM ANIMALS 131 



more protein there should be in the ration, the amount de- 

 creasing with the age of the animal until it reaches maturity. 

 Thus especial attention should be given to the protein con- 

 tent of the rations of all growing animals, remembering that 

 it is better to feed a little too much protein than not enough. 

 In addition to the quantity of protein, the quahty of the 

 protein should also be considered, in order to make sure that 

 the ration is not deficient in any of the essential amino acids. 



If the animals are to be used for meat or work, especial 

 emphasis need not be laid upon the carbohydrates and fat 

 or energy content of the growing ration, so long as it is 

 sufficient. However, if they are to be used for breeding pur- 

 poses, care should be taken to limit the amounts of carbohy- 

 drates and fat of the ration, or the animals may become so 

 fat as to produce barrenness. This is, often the case with 

 show animals which have become too fat. 



Mineral matter, especially calcium and phosphorus, is 

 absolutely essential to the proper development of the growing 

 animal. Ordinarily, except sometimes in the case of pigs, 

 a properly balanced ration will contain sufficient phosphorus, 

 as most of the nitrogenous feeds are high in phosphorus. 

 If a legume hay is fed, there probably will be sufficient 

 calcium in the ration. Otherwise additional calcium or 

 phosphorus must be supplied by adding feeds which are rich 

 in these elements. In case of pigs, it is usually considered 

 good practice to allow them free access to a mineral mixture. 

 (See page 79). 



Haecker, at the Minnesota Experiment Station,^ after 

 many years of experimentation, proposes the following table 

 as expressing the requirements of growing fattening cattle. 



1 Unpublished data. 



