GRASSES OP IOWA. 4B3 



CALCULATION OP A PEEDING RATION. 



"Let it be assumed, for the illustration, that a farmer has a 

 cow weighing about 900 pounds and giving about 30 pounds of 

 milk a day, to which he wishes to feed a ralioQ balanced 

 according to the Wolff-Lshmaan standard; that he has hay 

 (timothy, Kentucky bluegrass, clover, etc., essentially 'mixed 

 grasses '), fairly mature corn silage, bran and cob meal, and 

 that he can buy cottonseed meal, Chicago gluten meal, Quaker 

 dairy feed, mixed (wheat) feed, Buffalo gluten feed and hominy 

 chops. How shall he proceed to figure out his ration? Refer- 

 ence to the standard shows that the 1,000-pound cow shou!d be 

 fed 32 pounds of dry matter, 3.3 pounds protein, 13 pounds 

 carbohydrates and 0.8 pounds ether extract, nutritive ratio, 

 1:4.5. The ether extract figures are multiplied by 2.25* and 

 added to those of the carbohydrates, and then all the figures 

 are multiplied by niue-tsnths. This latter is done because a 

 900-pound cow weighs nine-tenths what a 1,000-pound cow 

 does, and is held, according to the standard, to need approx- 

 imately but nine-tenths the nutrition. As a matter of fact, she 

 probably needs a little more than this. 



"0.8X2.25 = 1.8. 13 + 1.8 = 14.8. 32.0 X .9 = 28 8. 3.3 

 X .9 = 2.97. 14.8 X .9 = 13 3. 



"The WolffLehmann standard for a 900-pound cow giving 

 30 pounds milk, therefore, requires that the daily food shall 

 contain 28.8 pounds total dry matter, 2.97 pounds digestiWe 

 protein, 13.3 pounds digestible carbohydrates and ether 

 extract; and, if this is fed, the nutritive ratio will be 1:4.5. 



"The next step is to supply these nutrients. The conven- 

 ience table (table IV) shows that of the feeds on hand bran 

 alone has a nutritive ratio (1:3.8) narrower than the standard. 

 The hay, sUageand cob meal have 'wide' ratios (1:10.0, 1:14.8, 

 1:13 9), all wider than the standard. Hence purchases must be 

 made, and these must be of go^ds with narrow ratios. The 

 materials available are found to have ratios as follows from 

 narrowest to widest: Cottonseed meal, 1:1.0; Chicago gluten 

 meal, 1:1.5; Buffalo gluten fesd, 1:2.4; mixed (wheat) feed, 

 1:3.9; Quaker dairy feed, 1:4 6, and hominy chop, 1:9.2. It is 

 at once perfectly clear that the latter two feeds will not aid in 

 balancing the ration, and that the mixed (wheat) feed will not 

 be of much avail. Hence choice should be made of one or 



* To reduce the ether extract to the same food value and— assumedly— feeding 

 V ilue as the carbohydrates. 

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