310 SCIENTIFIC FEEDING OF ANIMALS 



fat (rye feeding meal by rice feeding meal) without 

 any change being made in the more active portions 

 of the food, it was found that 



One cow gave 1-85 kg. more milk and 29 g. more fat 



Another 2-24 less 66 less 



o-oi more ,,21 



)J )) O'7I }j )) 55 O 5, ,, 



Observations of this kind, which anybody can make 

 in practice, show how extraordinarily changeable is 

 the influence of individuality upon the production 

 of milk. They teach also how deceptive are the 

 results of experiments carried out upon a small 

 number of animals. 



(b) The period of lactation. 



The formation of milk, which begins at the time 

 of calving, does not always remain at the same 

 level, but in time decreases until, usually some 

 time before the next calving, no more milk is formed 

 and the cow is dry. Here also the individuality of 

 the animal gives very variable results. With many 

 cows the yield of milk increases for several months 

 after calving, remains for some considerable time 

 at the highest yield, then falls quickly or slowly 

 and remains for a period at that level ; but here again 

 no universally applicable rule exists. Generally 

 in the course of lactation the percentage quantity 

 of dry matter and fat increases, but to this also 

 there are plenty of exceptions. 



