XIV.] 



VARIATIONS OF FAT IN MILK 



279 



milk that is possible. Table XXVII I. shows the amount 

 of butter fat in the successive portions of milk taken 

 from the cow. 



Table XXVIII.— Composition of Successive Portions of 

 Milk taken from the Cow. 



7. Other causes of disturbance. — It is found that 

 cows are extremely susceptible animals, easily disturbed 

 both in the yield and composition of their milk by any 

 external causes which excite the animals. Change of 

 location into a new building, going out to grass, any 

 sudden fright, a thunderstorm, or a marked change of 

 temperature, will often be found to exert a considerable 

 influence upon both the yield and the composition of 

 milk. In fact, if the composition of the milk of a single 

 cow be examined day by day, it will be found to show 

 a number of irregular variations both in amount and 

 composition, which are to be accounted for by minor 

 disturbances of this kind. It is thus necessary, when 

 one wishes to ascertain the average composition of the 

 milk produced by a given cow, to make up a composite 

 sample representing the milk yielded during at least 

 one week. This should be done by putting aside after 

 each milking a small quantity proportional to the yield 

 on that occasion, a preservative being added to the 

 mixed sample in order to retain it in a condition for 

 analysis up to the end of the week. 



From these particulars it will be seen that the farmer 

 engaged in the production of milk should first of all pay 

 attention to the yield and composition of the milk 

 produced by each individual cow. By keeping his 



