280 DAIRY CATTLE AND MILK PRODUCTION 



maintenance, and to this adds the amount of each necessary 

 to supply what is needed for the milk. The maintenance 

 requirements are as follows : 



The maintenance requirement naturally increases with the 

 size of the animal, but not in direct proportion. 



Armsby suggests .3 therm in energy value and .05 pound 

 of digestible protein for each pound of milk. This standard 

 for milk production is based upon milk containing about 4 

 per cent of fat and 13 per cent of total solids. However, no 

 one figure given could be accurate for milk of all degrees of 

 richness. 



Calculating a Ration. Let it be assumed that it is desir- 

 able to calculate the ration for a 1150-pound cow producing 

 30 pounds of milk per day. According to the preceding 

 table, there would be required approximately the following 

 for maintenance: 



Digestible Protein 55 Ib. 



Energy 6.50 therms 



For the production of 30 pounds of average milk there 

 would be needed: 



Digestible Protein (30 x .05) . . 1.50 Ib. 

 Energy (30 X. 3) 9.00 therms 



