174 THE CHEMISTRY OF CATTLE FEEDING 



form of fat; but the quantity of this ingredient should not, 

 as a rule, exceed the equivalent of ^ of the starch. 



The quantities calculated by the formulae are strictly those 

 required for milk production, as apart from maintenance, 

 increase, work, etc. If there be any question of such, a 

 further addition should be made on account of it. For 

 instance, nothing has been allowed for the work of digestion 

 of that part of the food given for milk production. The point 

 is not, perhaps, of much importance, because such foods 

 should be, and usually are, of a highly concentrated and 

 readily digestible character. Still, in many of them, about 

 5 per cent, is lost in this way, as shown in the tables (p. 166), 

 and, on a strict calculation, allowance should be made for 

 this. The maintenance ration, previously considered, includes 

 the amount spent in digesting that portion of the food, but not 

 the amount spent in digesting the concentrated food given for 

 milk production. 



Feeding Standards. In order to make a feeding standard 

 for milk cows, the nutrients of the maintenance ration are 

 added to those of the food required specially for milk pro- 

 duction. The former varies according to the size of the 

 animals, and the latter according to the yield of milk. If \ Ib. 

 of digestible protein and 8*3 Ibs. of non-nitrogenous nutrients, 

 reckoned as starch, be taken as the standard for maintenance 

 of cows of 1000 Ibs. live weight (cf. p. 134), the feeding 

 standards would be as follows : 



The objections to such feeding standards for milk cows 

 are similar to those offered in regard to the standards for 

 working horses (p. 160), but they are even more weighty and 

 perhaps more obvious. The two variable factors the size 



