MILK PRODUCTION 



495 



The percentage utilization in milk production alone may also 

 be approximately estimated from Kellner's figures by sub- 

 tracting from the metabolizable energy available for production 

 the amounts estimated to be required for the production of the 

 observed gain of body tissue. The results of this calculation 

 are shown in the following table. A similar computation by 

 Kellner based on his estimated starch values gives substantially 

 the same results. 



TABLE 133. UTILIZATION OF METABOLIZABLE ENERGY IN MILK PRO- 

 DUCTION 



590. Partial energy balances. Partial energy balances of 

 two cows which made but slight gains in live weight are re- 

 ported by Jordan, 1 the maintenance requirement being esti- 

 mated from the live weight and the excretion of methane com- 

 puted from the digestible carbohydrates. Assuming that there 

 was no gain or loss of fat or protein by the body, the following 

 comparisons can be made : 



TABLE 134. UTILIZATION OF METABOLIZABLE ENERGY IN MILK PRO- 

 DUCTION 



1 N. Y. (Geneva) Expt. Sta., Bui. 197, pp. 24-32 and 2oth Rpt. (1901), p. 29. 



