118 Feeds and Feeding. 



. . 



starch values." 3 He found that on the average 1 lb. of digestible 

 starch fed to the ox in excess of maintenance requirements pro- 

 duced 0.248 lb. of body fat. (85) Taking 1 lb. of digestible starch 

 as his unit, he gives the following starch values for the digestible 

 nutrients in feeding stuffs, based on the amount of body fat these 

 several pure nutrients will form if fed to the ox: 



In 1 lb. of digestible Starch value 



Lbs. 



Protein _ 0.94 



Nitrogen-free extract and fiber 1.00 



Fat in roughage, chaff, roots, etc 1.61 



Fat in cereals, factory and mill by-products 2 . 12 



Fat in oil-bearing seeds and oil meal 2. 41 



Kellner further found that the net nutritive value of certain 

 concentrates, such as grains and seeds, oil cake, roots, and slaugh- 

 ter-house by-products, was the same as that obtained when the 

 several pure nutrients in them were fed separately. If the amounts, 

 in pounds, of the several digestible nutrients in 100 Ibs. of feeds 

 of this class are multiplied by the starch values of the respective 

 nutrients they contain, and the products added, the sum will rep- 

 resent the starch value of 100 Ibs. of such feeds. With other feed- 

 ing stuffs the work of mastication and digestion materially re- 

 duces their actual net value. The following deductions should 

 accordingly be made from the values found as before : 



Deduction 



Class Per ct. 



Mill and factory refuse feed 5-30 



Soilage crops HX-20 



Silage 20-40 



Hay 30-50 



Straw 50-70 



Kellner affirms that despite the vast amount of study given to 

 the subject there are still many gaps in our knowledge of the actual 

 net value of the different feeding stuffs. In his own case such values 

 have been determined by actual experiments with only a limited 

 number of typical representatives of the different classes of feeding 

 stuffs when fed to the mature fattening ox. For the numerous other 

 feeds, and especially for other classes of animals, the net starch 

 values found by computation must be regarded only as approxi- 

 mations, which are helpful until the actual net values of such feeds 

 to the different classes of animals have been found. 



1 Land. Kal., 1909, 1, pp. 103-119; Ernahr. landw. Nutztiere, 1907. 



