202 ELEMENTS OF FARM PRACTICE 



From the last table it is an easy matter to determine 

 the amount of nutrients required to produce a given number 

 of pounds of milk of a given per cent of fat. For example, 

 a cow that gives 15 lbs. of 4% milk will require, for its 

 production, 15 times as much of the nutrients as is required 

 to produce one pound of milk of the same quality. (See 

 star in table on the preceding page.) 



Fifteen times .048 lbs. of protein, .23 lbs. of carbohydrates 

 and .016 lbs. of fat equals .72 lbs. of protein, 3.45 lbs. of carbo- 

 hydrates and .24 lbs. of fat. Thus, it will be seen that a 

 cow requires .72 lbs. of protein, 3.45 lbs. of carbohydrates 

 and .24 lbs. of fat, simply for the production of milk. In 

 addition to this, she must be supplied with feed for bodily 

 maintenance. If the cow weighs 1,100 lbs. she will re- 

 quire 11 times .07 lbs. of protein, .7 lbs. of carbohydrates 

 and .01 lbs. of fat (the amount required to maintain 100 

 lbs. live weight) or .77 lbs. of protein, 7.7 lbs. of carbohy- 

 drates and .11 lbs. of fat. We know, then, that a cow 

 weighing eleven hundred pounds, and giving 15 pounds of 

 4% milk requires daily: 



Pro. C. H. Fat 



For maintenance .' 77 7.7 .11 



For 15 lbs. of 4% milk 72 3.45 .24 



Total daily requirement 1.49 11.15 .35 



From the above it will be seen that, to determine the 

 requirements of a cow, one must know approximately her 

 weight, her daily milk production and its per cent of fat. 

 If these facts are known, it is, with the table, a very simple 

 mathematical problem to determine her daily needs. 



Questions: 



1. What do you understand by the term "food of maintenance?" 



2. How have feeders found out how much feed animals require 

 for maintenance? 



3. Why does a cow require more feed when giving 20 lbs. of 4% 

 milk than when she is giving 10 lbs. of 4% milk? 



4. What three factors must be known in order to determine the 

 daily feed requirements of a cow? 



Arithmetic: 



1. For bodily maintenance a cow requires .07 lbs. of protein, 

 .7 lbs. of carbohydrates and .01 lbs. of fat per 100 lbs. live weight. 

 How many pounds of each nutrient are required to maintain a cow 

 weighing 1,050 lbs? 



