262 DAIRY CATTLE AND MILK PRODUCTION 



the cutting down of the ration one half would remove all 

 available feed for milk production. However, the animal 

 would not cease producing milk at once. This is a point of 

 great importance in feeding cows, and a lack of such knowl- 

 edge leads to serious errors in feeding. The milk-producing 

 function is so strong that the cow will continue to produce 

 milk for some time, even when the feed is insufficient, utilizing 

 the reserve material which has been accumulated in the body 

 in the past. This always happens in the case of a heavy- 

 milking cow during the first few weeks after the birth of the 

 calf. At this time, it is not generally possible, and not desir- 

 able on account of the condition of the animal, to feed her 

 a sufficient quantity of feed to supply the nutrients necessary 

 to produce the milk; and even if the feed was offered, the 

 appetite is not usually strong enough to cause the necessary 

 amount of feed to be taken to prevent loss in weight. As 

 a rule, all heavy-milking cows decline in weight for the first 

 two or three weeks, and occasionally for ten weeks, after 

 calving, which means that milk production has been in excess 

 of the feed supplied for that purpose. The same thing 

 happens in the case of the cow that is not fed a sufficient 

 ration for the amount of milk that she is producing. She 

 may continue to produce considerable milk for a while by 

 drawing on the reserve material of the body, but as soon as 

 this -is exhausted, the production of milk must come down 

 to the amount available for this purpose, above the ration 

 of maintenance. When the feed is in excess, the cow begins 

 to store reserve material on her body. If the amount of 

 milk produced by a cow varied directly with the feed, and 

 she did not store up nutrients at one time and draw on reserve 

 material at another, it would simplify the problem of feeding 



