THE HAECKER STANDARDS 



411 



Net nutrients used by mature cows — Continued 



" Given the daily yield of milk in pounds, its percentage of butter- 

 fat, and the weight of the cow expressed decimally, it is an easy 

 matter to determine the required ration. As an illustration, suppose 

 a mature cow weighs 825 pounds, gives 20 pounds of milk daily 

 testing 4 per cent butter-fat. One pound of 4 per cent milk re- 

 quires of protein .0467, carbohydrates .214, and of ether extract 

 .0159; multiplying these factors by 20 it is found that for the 

 production of milk the cow needs .934 of protein, 4.28 of carbohy- 

 drates, and .318 of ether extract. For food of maintenance, mul- 

 tiply .07 protein, .7 carbohydrates and .01 of ether extract (main- 

 tenance formula) by 8.25, which gives protein .578, carbohydrates 

 5.78, and ether extract .082 ; adding to this the nutrients required for 

 milk production, we have 1.51 of protein, 10.06 carbohydrates, and 

 .40 ether extract, the nutrients required in the ration. They should 

 be supplied in such manner with reference to bulk that the ration 

 will satisfy the appetite. A ration like this should be largely made 

 up of roughage." (Haecker.) 



For a cow weighing 850 pounds and yielding 40 pounds of 4 per 

 1 Maintenance standards not detailed here. 



