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IOWA ACADEMY OF SCIENCE 
milk had] been added to this ration in addition to the feeds al- 
lowed, this -pig wonld have made even a greater showing than it 
did. At any rate, there is the suggestion that this pig did re- 
markably well under this free-choice scheme of feeding and the 
indications are that the gains were greater than they would 
have been had ordinary methods been practiced. Inasmuch as 
this is the biggest pig for the age that has ever been fed in 
Experiment Station work, to our knowledge, this suggestion 
seems all the more real and true. 
The palatability^® of the specific feeds is not at all constant, 
but much depends upon the stage of development of the pig and 
on his environment; the pig seems to adjust himself automat- 
ically, perhaps unconsciously, to the conditions at hand. If he 
is growing he eats a larger proportion of protein, or better say, 
a. mixture heavier in amino-acids, than after he attains his 
growth, when he is simply maintaining himself. That feed, 
therefore, which is palatable to swine when they are small, 
young, and immature may be relatively distasteful when they are 
large, old, and quite mature. It would seem that that feed is 
the most palatable which most nearly satisfies the appetite, this 
ultimately meaning the satisfaction of the specific cells in need. 
The feeding standards which have been proposed for growing 
and fattening swine are still in’ a somewhat crude form. At- 
tention is given primarily to the apparently digestible protein, 
carbohydrates, and fats; ratio of crude nutrients (that is, the 
number of pounds of carbohydrates or its equivalent present 
with every pound of protein) ; dry matter; and sometimes water. 
The Wolff -Lehmann standard, which has been the foremost one 
considered by animal husbandmen, was first proposed by Wolff, 
a G-erman scientist. This standard has been supplemented by 
the work of C. Lehmann of the Berlin Agricultural High School, 
Germany. This standard, based on the crude nutrients required 
per thousand pounds of live weight, is shown in Plates XLII, 
XLIII, and XLIV. The Illinois or Dietrich standard was pro- 
posed by Dietrich^® of the Illinois Experiment Station. The DieL 
3®For further discussion of this theme see, — Bvvard, John M. : The Free- 
Choice System of Self-Feeding Swine, Nov. 1914. Am. Soc. An. Prod., Proc. 
1914. (Not yet from Press in July, 1915.) 
sTWolflc, von. Dr. Emil, 1864, Mentzel and von Lengerke Agricultural Cal- 
endar; see also Henry: Feeds and Feeding, 1912, Twelfth edition, p. 590; 
Dietrich, William: Swine, 1910, p. 144; Woll, F. W. : Productive Feeding of 
Farm Animals, 1915. p. 294; and Jordan, Whitman Howard; 1901, Note 5, 
p. 435. 
38Dietrich, William; Swine, 1910. The Revised Standard was given to Ihe 
author by Dietrich in May, 1914, which standard is figured on the crude 
nutrient basis in Plates XLII and XLIII. 
