194 ANNUAL REPORT. OF THE Off. Doc. 



♦PROGRAM— SECTION A. 



ANIMAL NUTRITION, 



Br Dr. H. p. Aumsbt, Director, Experiment Station, State College, I'a. 



Mr. Chairman: I have taken up the question of ''The Protein Sup- 

 ply of Dairy Cows" as my topic because the subject of "Animal Nu- 

 trition" is too large for treatment in one hour, therefore, with the 

 consent of Director Martin, I will take up this single topic. In the 

 first place, take a simple case. Suppose you do not give an animal 

 any food at all, pasture it for a time, wc find if we examine the ex- 

 creta, that it is still breaking down the protein of the body. We 

 find the urea and the other substances which come from this break- 

 ing down of the substances still present. In other words, that means 

 that the necessary operations of the vital machinery used up protein 

 and if you let the machine run long enough without any protein to 

 make good this wear and tear, it will break down, that is to say^ an 

 animal can be starved to death by leaving out the protein of its food 

 while giving it plenty of other material, just as if you supply plenty 

 of coal under the boiler of an engine, and neglect to supply any iron 

 and steel for repairs until it wears out. The engine will run for a 

 time, run longer than the animal, but ultimately will break down. 

 A certain amount of protein in the food is absolutely necessary to 

 the vital machinery in repair. A minimum of protein is essential 

 for maintenance, that is, you must have a certain amount, not a very 

 large amount, to keep up the repairs, so to speak, of the animal; to 

 make good 'the protein that always will break down, and the break- 

 ing down of it you cannot prevent by any sort of advice. You must 

 have a certain amount of protein to maintain the animal. 



Now, what happens if we give it more? In the mature animal 

 you might think, at first blush, that if you give it enough protein to 

 maintain its tissues that you w'ould produce more lean meat in the 

 animal. As a matter of fact, you don't. If you give it more protein 

 it simply breaks down, and you get a corresponding increase in the 



•Note.— The program was arranged in two .sections. Section A and Section 8. The two classes were 

 scheduled to meet at the same hour. Section A in the main room and Section B in room 121. The pro- 

 ceedings are arranged under the dififerent sections. , 



