Principles and Practice of Stock Feeding. 11 



yet she gave in her milk 63 pounds of fat. This extra fat could not have 

 •come from previously stored bodily fat, since the cow gained 47 pounds in 

 weight, and was judged to be fatter at the end than at the opening of the 

 trial. 



4. Digestibility 



A chemical analysis of a fodder or feed shows the crude nutrients it con- 

 tains, but gives no hint as to their availability as food. All food eaten is 

 not digested. Such as is dissolved by the sundry ferments of the digestive 

 tract is assimilated; the residual undigested portion forms the solid excreta 

 or dung. The proportions of the total amount of a crude nutrient which 

 may be digested from a given fodder or feed is influenced by sundry condi- 

 tions. The kind of animal, its breed, individuality, age and condition as 

 regards work are important. Likewise the quantity of fodder fed, its succu- 

 lence or dryness, its method of preparation, stage of growth, conditions 

 affecting it like weather or long keeping and the addition of concentrated 

 foods to a ration variously affect results. Among the more important points 

 which have been determined by experiment may be cited the following : 



Animal. Kind. — Horses digest less fiber and ether extract but nearly 

 •or quite as much protein and nitrogen-free extract as do ruminants, (cows, 

 sheep, etc). The latter digest the same kind of food essentially alike. 

 Swine seem to digest the crude fiber of certain feeds better than either 

 horses or ruminants. 



Breed and age. — No effects have been determined which may be ascribed 

 to differences in breed or age. 



Individuality. — Variations due to this cause are wide, wider oftener than 

 between differing breeds and species. 



Rest and work. — Many tests have shown as a rule but slight differences. 



Fodder. Quantity. — A large number of tests have shown practical 

 uniformity in digestibility regardless of the amount eaten of a given food. 



Green or dry. — If cut at the same time and dried without loss of leaves, 

 drying does not affect digestibility. In actual practice, owing to loss of 

 leaves, dried fodders are less digestible than when green. 



Method of hay making. — Hay made in the most rapid manner, with the 

 least possible handling, and dried only enough to insure its keeping, loses 

 less of its finer and more digestible portions than when slowly made, much 

 tumbled, exposed to rain, etc. 



Preparation. — Moisture, dryness, warmth, or cold affect results but 

 slightly. Cooking avails nothing, but cutting or "chaffing" at times does 

 aid somewhat. 



State of growth. — As a rule digestibility lessens as growth advances. 

 The largest yield of digestible nutrients is however more important than ex- 

 treme digestibility. This is not attained by frequent cuttings of very young 



