A PRACTICAL FEEDING RATION. 197 



has on hand or can procure. The feeding standards com- 

 monly adopted as basis for calculations of this kind are 

 those of the German scientists, Wolff and Lehmann. 

 Those standards give, then, the approximate amount of 

 dry matter, digestible protein, carbohydrates, and fat 

 which the different classes of farm animals should re- 

 ceive in their daily food in order to produce maximum 

 returns. We have seen -that a fair amount of digestible 

 protein in the food is essential in order to obtain good 

 results. The proportion of digestible nitrogenous to 

 digestible non-nitrogenous food substances therefore be- 

 comes important. This proposition is technically known 

 as Nutritive Ration, and we speak of wide nutritive ratio, 

 when there are six or more times as much digestible 

 carbohydrates and fat in a ration as there is digestible 

 protein, and a narrow ratio, when the proportion of the 

 two kinds of food materials is as 1 to 6, or less. 



The feeding standards given in the following tables 

 may serve as a fairly accurate guide in determining the 

 food requirements of farm animals; and it will be noticed 

 that the amounts are per 1,000 pounds live weight, and 

 not per head, except as noted in the case of growing 

 animals. They should not be looked upon as infallible 

 guides, which they are not, for the simple reason that 

 different animals differ greatly both in the amounts of 

 food that they consume and in the uses which they are 

 able to make of the food they eat. The feeding standard 

 for milch cows has probably been subjected to the closest 

 study by American experiment station workers, and it 

 has been found in general that the Wolff-Lehmann -stan- 

 dard calls for more digestible protein (i. e., a narrower 

 nutritive ration) than can be fed with economy in most of 

 the dairy sections of our country, at least in the central 

 and northwestern states. On basis of investigations con- 

 ducted in the early part of the nineties, along this line, 

 Prof. Woll, of Wisconsin, proposed a so-called American 

 practical feeding ration, which calls for the following 

 amount of digestible food materials in the daily ration of 

 a dairy cow of an average weight of 1,000 pounds. 



Digestible protein 2.2 Ibs. 



Digestible Carbohydrates. .13.3 Ibs. ) carbohydrates+fat 



Digestible fat 7 Ibs. X 2 /4, 14.9 Ibs. 



Total digestive matter 17.1 Ibs. ) protein+carbohy- 



drates-ffatx2 1 / 4. 

 Nutritive ratio 1:6.9 



