20 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 



production of body-weight increase. Their method was essen- 

 tially to divide the weights or nutritive values of each feed 

 by the weight of butter-fat produced. For the production of 

 1 lb. of butter-fat they were thus able to show in the various 

 rations that a certain quantity of hay or prickly pear, pro- 

 portional to their values for production, and equal quantities 

 of grain were required. 



By a similar method applied to the data for Groups 1 and 

 3 (Table 12), the author obtained the figures shown in Table 

 13 :— 



Table 13. — Starch EQnvALENTS for Production of One Pound of Butter-fat and 

 Accompanying Increase. 



It was thought, however, that the roughages could be 

 better compared if the rations provided only for maintenance 

 and milk-production without body- weight increase, and the 

 figures were subsequently adjusted by subtraction from the 

 nutrients of the roughage feeds of amounts adequate to the 

 gains noted.* In addition, on the assumption that the nutrients 

 of the hay and meal were of equal value in the rations, the 

 slight inequalities of the quotients for meal have beer 

 smoothed out by conversion of the excess in one of the pair 

 of meal quotients to hay nutrients. By this method of pro- 

 cedure there were obtained the following results, which are 

 thought to be at least as accurate as those of Woodward, 

 Turner, and Griffiths, viz. : — 



Prickly pear fed as sole roughage (high amounts), 7-32 lb. 

 starch equivalent prickly pear = 3-90 lb. starch 

 equivalent hay, or 1-88 lb. starch equivalent prickly 

 pear = 100 lb. starch equivalent hay. 



Prickly pear fed as part roughage with hay (medium 

 amounts), 3-48 lb. starch equivalent prickly pear = 

 2-39 lb. starch equivalent hay; or 1-41 lb. starch 

 equivalent prickly pear =^ TOO lb. starch equivalent 



hay. 



* Viz., 3-0 starch equivalent for 1 lb. body-weight increase (6, p. 198). 



