46 Report of the Department of Animal ECusba'ndry of the 



[NTRODUCTIOK 



( )jic of the most important questions to consider in the feeding 

 of poultry is the relative efficiency of the protein or nitrogenous 

 matter in different foods and the economy of their use. While the 

 several principal constituents of foods may all be sources of 

 energy and of material for the large amount of fat stored in the 

 egg. and in the body, nothing except the protein, or several nitro- 

 genous constituents, can supply the necessary nitrogen. Inas- 

 much as the more common and cheaper foods all contain heat and 

 fat producing constituents in abundance, the source of the nitro- 

 gen naturally receives first consideration. 



As a rule some forms of protein can be obtained at much less 

 cost in grain foods and various by-products derived from grains 

 and seeds than other forms of protein from animal foods. It is 

 therefore of immediate practical importance to know whether the 

 cheaper rations, consisting entirely or largely of vegetable foods, 

 are efficient enough to be economical, or whether a large propor- 

 tion of animal food is essential. The amount of protein that can 

 be obtained by the common fowl from the coarser vegetable foods 

 such as clover, is relatively small, although it is important to 

 utilize these foods as far as possible. 



The natural animal foods eaten by fowls contain usually a high 

 percentage of nitrogenous matter and not a large proportion of 

 fat. Many of the artificial foods, except such as dried blood and 

 skim-milk, contain usually, besides the nitrogenous matter, a high 

 percentage of fat, which often is not especially desired in com- 

 pounding the ration. For instance, both earth worms and grass- 

 hoppers contain nearly ten times as much protein as fat, while 

 ordinary fresh-cut bone contains about equal amounts of protein 

 and fat. 



CONDITIONS OF THE EXPERIMENT. 



During two years a number of feeding experiments have been 

 made in growing fowls on rations containing greater or less pro- 

 portions of animal foods. Those experiments in which rations 



