CHAPTER XI 

 FOOD REQUIREMENTS OF ANIMALS. 



The young growing animal. The distinct and characteristic 

 feature of the growth of young animals is the rapid formation 

 of soft tissue and bone. For this purpose there must be an 

 abundant supply of protein and suitable ash. 



This is true for all young domestic animals. The daily in- 

 crease in live weight of a well nourished calf is very considerable 

 and may be as large as that of a well-fed, mature steer. It may 

 amount to 2 pounds per day ; and much less than this would be 

 regarded as unsatisfactory. Lawes and Gilbert analyzed the 

 entire body of a fat calf with the following results: 



Per cent 



Water 64.6 



Ash 4.8 



Protein 16. * 



Fat 14.1 



Based on this analysis the daily increase of 2 pounds live weight 

 in a growing calf would mean a storage of about 0.33 Ib. of pro- 

 tein and 0.28 Ib. of actual fat, or a total increase of 0.61 Ib. of 

 dry body material. This may be equal to one-fifth or more of 

 the total dry substance of the ration. European investigations 

 with calves have shown that one pound of milk solids, practically 

 all digestible, produced one pound of increase in live weight. Be- 

 cause of the water content of this increase, the actual dry matter 

 is equal to about one-third of a pound. Further, these studies 

 showed that 70 per cent of the protein of the food was retained 

 in the bodies of the calves and 72 per cent of the phosphoric acid 

 and 97 per cent of the lime held for skeleton and tissue expansion. 

 On an assumed consumption of 10 pounds of average milk daily, 

 this would mean a retention of 6.4 grams (approximately one- 

 fifth of an ounce) of phosphoric acid and 8.7 grams of lime. 



