328 NUTRITION OF FARM ANIMALS 



quirement of sheep for the growth of wool is considerably greater than 

 that of cattle for the growth of hair, the absolute difference, after all, 

 does not add very greatly to the total maintenance requirement. 



The current feeding standards for the maintenance of sheep call 

 for i. 0-1.6 Ib. of digestible crude protein per 1000 pounds live 

 weight, apparently upon the basis of Henneberg and Stohmann's early 

 experiments (382) in which 1.3 Ib. of crude protein or i.o4lb. true 

 protein produced but a slight gain of body protein in addition to the 

 growth of the wool. There can be little doubt, however, that Henne- 

 berg and Stohmann's sheep received a surplus of protein above the 

 actual maintenance requirement. 



In a series of 20 digestion and metabolism experiments by Schulze 

 and Marcker, 1 decidedly smaller amounts of protein proved sufficient 

 to maintain nitrogen equilibrium, the average of 6 experiments in 

 which no loss of body protein was observed being 0.653 Ib. digest- 

 ible crude protein per 1000 pounds live weight. It is evident, then, 

 that the protein supply of sheep can be reduced much below the 

 amount fed in Henneberg and Stohmann's experiments without lead- 

 ing to a loss of body protein. 



The most satisfactory data regarding the minimum require- 

 ment of sheep are afforded by Katayama's 2 investigations, in 

 which increasing amounts of nearly pure protein (" aleuronat ") 

 were added to a basal ration very poor in protein, consisting of 

 hay, oat straw, starch and cane sugar. The protein in every case 

 was substituted for a corresponding amount of starch, so that 

 the total energy of the ration remained substantially unchanged. 

 On the average of two animals, 0.41 Ib. digestible true protein 

 per 1000 pounds live weight was sufficient to maintain the 

 nitrogen balance. Since, however, the growth of wool must 

 have gone on, with a corresponding storage of nitrogen, there 

 must have been an equivalent loss of protein by the active 

 tissues of the body. 



If to the minimum of 0.41 pound there be added 0.14 Ib. 

 per 1000 pounds live weight for the growth of wool, it appears 

 that the minimum protein requirement for the maintenance of 

 mature sheep is in the neighborhood of 0.55 Ib. It is inter- 

 esting to note that the actual maintenance requirement for 

 the body tissues is apparently quite as low relatively as for 

 cattle. 



1 Wolff ; Die Ernahrung der landwirtschaftlichen Nutetiere, p. 300, 



2 Landw. Vers. Stat., 69 (1908), 321. 



