FEEDING DAIRY CATTLE 



247 



per 'head daily (Figs. 51 and 52). Only exceptionally large pro- 

 ducers will give good returns for more than six or eight pounds of 

 grain feed daily, with abundant roughage of good quality at hand. 

 A common rule is to feed as many pounds of grain feeds a day per 

 head as the cows produce pounds of butter fat during the week., 

 and to feed as much roughage in addition as they will eat up clean. 

 Another rule is to feed a pound of grain feed for every 3 to 5 pounds 



FIG. 51. The "meal cart" used for weighing concentrates for the individual cows in the 

 herd. (Ottawa Station.) 



of milk yielded by the cows, according to the character of the 

 roughage fed, the quality of the milk, and the intensity of the sys- 

 tem of feeding practiced (see also p. 77). 



Mineral Requirements. Investigations at the Ohio Station 

 have shown that good dairy cows, while not on pasture, are un- 

 able to maintain mineral balances during the time of heavy pro- 

 duction, and draw on their body reserves, especially for the amounts 

 of calcium, magnesium, and phosphorus necessary for the elabora- 

 tion of the milk. Such a deficiency may have far-reaching re- 



