410 NUTRITION OF FARM ANIMALS 



low protein (maize) rations the weights of blood, of internal 

 organs and in some cases of certain individual muscles were 

 relatively less than with comparable animals receiving the 

 high protein (mixed) rations, while on the other hand, the 

 deposits of adipose tissue appeared notably greater in the maize- 

 fed animals. 



Since these investigations were made it has become a well-recog- 

 nized fact that the mixed proteins of maize are inadequate to sup- 

 port rapid growth (783) and the results reached are to be regarded 

 as being to a considerable degree the expression of this qualitative 

 deficiency. 



As regards the quantitative aspect of the experiments it is to be 

 remarked that in most instances the difference between the rations 

 as regards protein was purposely made large. While the experiments 

 have made it clear that exclusive maize feeding fails to afford an ade- 

 quate supply of protein for growing pigs, it does, not follow that as 

 large quantities of protein as were contained in the contrasting rations 

 were necessary. In the later Wisconsin experiments especially, as 

 the writer has pointed out, 1 the gain in live weight was often little 

 greater on the high protein than on the low protein rations and some- 

 times even less. 



Furthermore, while the animals were compared more or less ex- 

 tensively as to the weights of the various organs at the close of the 

 feeding, and in one instance at least the carcasses were analyzed, the 

 experiments were not of the nature of comparative slaughter tests 

 and did not afford data for computing the actual amount of protein 

 gained. Moreover, the results upon the carcasses analyzed 2 seem to 

 indicate that the rations affected the adipose tissue as to its distribu- 

 tion through the carcass rather than as to its total amount. 



Finally, the striking results as to general thrift, and especially as 

 to the growth and strength of the bones, are probably to be attributed 

 to differences in the ash supply (496) , quite as much as to differences 

 in the protein supply. 



On the whole, while these investigations are valuable from 

 the standpoint of practice as a demonstration of the ill effects 

 of a deficient amount or quality of protein, it cannot be said 

 that this class of experiments affords very definite information 

 as to the actual protein requirements of pigs. 



1 U. S. Dept. Agr., Bur. Anim. Indus., Bui. 108 (igo8), p. 74. 



2 Iowa Expt. Sta., Bui. 48 (1900), pp. 373-451; U. S. Dept. Agr., Bur. Anim. 

 Indus., Bui. 108, p. 75. 



