PKODUCTION OF MILK 207 



supplied and milk produced. One gram of cows* milk, 

 containing 13 per cent, of dry matter, will have a heat 

 value of 0*755 Calorie. If we might take food at 

 the production value shown in the experiments with 

 fattening oxen — 1 gram of starch, for instance, as stor- 

 ing up increase equivalent to 2'2 Calories — then 1 lb. 

 of starch, or rather its equivalent in digestible food 

 containing a sufficient proportion of albuminoids, would 

 produce nearly 3 lbs. of milk. The return obtained 

 from a good cow is, however, more than this. The 

 proportion of fat yielded by carbohydrates is probably 

 nearly the same in the cow as in the ox, but the 

 albuminoids of the food are used far more economi- 

 cally than in the ox, a large portion being stored up 

 without undergoing any serious loss. 



The return from the food supplied to the cow is also 

 complicated by the fact that a part of the return 

 appears as a young calf. Hagemann reckons a newly- 

 born calf as weighing about 88 lbs., and as containing 

 22 lbs. of albuminoids, 3*3 lbs. of fat, the rest being 

 water and ash constituents. In the first half of the 

 lactation period the product of the food appears chiefly 

 as milk ; in the latter portion of the lactation the 

 formation of the calf and the storing up of animal 

 increase becomes more considerable, and the return 

 in milk falls off. 



An ample extent of good pasture furnishes sufficient 

 food for a cow in full milk, and it is only on inferior 

 land, in a dry season, or on a crowded pasture, that 

 the addition of concentrated food becomes necessary. 

 In winter feeding on hay, straw, roots, and silage, the 

 addition of concentrated foods containing a consider- 

 able proportion of albuminoids is imperative if a good 



