i86 THE CHEMISTRY OF CATTLE FEEDING 



This ration is extremely faulty in every respect. The 

 amount of coarse fodder is nearly twice as much as is required 

 for maintenance. The balance, no doubt, is available for milk 

 production, but such foods are neither suitable nor economical 

 for this purpose. The total amount of nutrients, and especially 

 of protein, is excessive. If all the hay and a third of the cake 

 were eliminated from this ration, it would still be sufficient for 

 the maintenance of cows of 1200 Ibs. live weight, and produc- 

 tion of 4 gallons of milk per day. 



The ration was used by an experienced farmer. He was 

 under contract to supply a certain quantity of milk, and was 

 afraid that if he reduced the rations the yield of milk would 

 diminish. The facts came to the author's knowledge in con- 

 nection with complaints regarding the quality of the milk. On 

 examination the milk was found to contain 5'i per cent, of 

 fat, but in other respects it was quite normal. 



In analysing rations from the point of view of efficiency 

 and pecuniary economy, as above, the coarse fodder is first 

 appropriated for maintenance, and any excess is treated as 

 available for milk production. If the whole of the coarse 

 fodder is insufficient, some of the more expensive concentrated 

 food must also be appropriated for maintenance, and only the 

 balance is treated as available for milk production. When 

 the quantity of coarse fodder is sufficient, the whole of the 

 concentrated food is thus available except what is spent on 

 the work of digesting it. The thermic energy of this portion 

 is, of course, added to that of the coarse fodder, but as it is 

 usually very small it may be ignored in practice. 



The thermic energy of the maintenance ration includes 

 that due to oxidation of the digestible protein. The protein 

 and non-nitrogenous nutrients which appear in the milk are 

 not oxidised, and they are more conveniently considered 

 apart. 



