252 THE PRINCIPLES OF AGRICULTURE 



be found that many animals can not profitably use 

 more than three or four pounds, while others can 

 use from ten to fifteen pounds, and an occasional 

 animal can profitably use a still larger amount. 



463. The amount of food that an animal can 

 or will eat must not be confounded with the 

 amount of food that an animal can profitably 

 use. Many animals can and constantly do pass 

 through their bodies a considerable amount of 

 food of which no use whatever is made, and 

 this, too, without interfering in any way with the 

 general health, digestive functions, or even with 

 the appetite. 



4c. Feeding standards 



464. Feeding standards show the amount and 

 proportions of the various nutrients that have 

 been found by experience to be best adapted 

 to the various purposes. A few are given : 



FOR EACH 1,000 POUNDS LIVE WEIGHT PER DAY. 



Digestible 



Dry Digestible carbohydrates Nutritive 



matter protein and fat ratio 



Oxen (maintenance) . 17.5 Ibs. 0.7 Ibs. 8.15 Ibs. 1: 12 



Horses at work . . .22.5 " 1.8 " 11.8 " 1:7 



Milk cows 24. " 2.5 " 12.9 " 1:5.4 



Growing pigs (young) 42. " 7.5 " 30. " 1:4 



465. In any given case, these or any stand- 

 ards may be advantageously varied to a con- 

 siderable extent. The standards are mere guides. 



