3 02 



NUTRITION OF FARM ANIMALS 



consumption of the feed i.e., by substantially the same gen- 

 eral methods used by Zuntz and Hagemann for the horse (385). 

 His results, computed per thousand square centimeters of body 

 surface and also per 5 pounds live weight in proportion to the 

 f power of the latter, were as follows : 



TABLE 53. NET ENERGY FOR MAINTENANCE OF HENS 



It would appear from the figures that the average main- 

 tenance requirement of a 5-pound hen may be estimated at ap- 

 proximately 72 Cals., while in periods of minimum muscular ac- 

 tivity it may fall as low as 56 Cals. The much higher figure 

 (93 Cals.) obtained in the periods when the hen was laying 

 does not represent maintenance simply, but includes also the 

 energy expended in the formation of the egg. As with all small 

 animals, the katabolism of the hen per unit weight is high, but 

 when computed per unit of surface it does not differ greatly 

 from that of other species. 



389. Metabolizable energy in maintenance rations. Ger- 

 hartz also determined the amount of feed required to main- 

 tain the live weight of his fowls and computes the correspond- 

 ing amounts of metabolizable energy to have been per 1000 sq. 

 cm. body surface. 



Rest period 102 Cals. 



Molting period 107 Cals. 



f 72 Cals. 

 ' ' ' ' \ 97 Cals. 



Brooding period 



Average 95 Cals. 



