854 Summary of Agricultural Experiments. [Jan., 



1,950 samples of milk were tested for fat, and of these 723 samples 

 were tested in duplicate, these including all samples containing less 

 than 3 per cent, fat, and all samples giving very high or very low 

 results. 



The results of the investigation are similar to those of last year. 

 The composition of the milk varied considerably from week to week; 

 and although no tests were made with the milk of individual cows this 

 shows that their milk must have varied considerably also. The limits 

 of variation are not so wide for the mixed milk of a number of cows 

 as for individual cows, the variations between the latter tending to 

 equalise the composition of the mixed milk, and in this connection the 

 effect of the size of the herd is of interest. Great similarity is exhibited 

 between Herds A and B, while Herds C and D, which are considerably 

 smaller than the other two, give much wider ranges of variation. 



No reason for the variations in fat content could be seen, beyond 

 the individuality of the ccw. Last year's results showed that the 

 variations could be observed when there were no disturbing influences 

 at work, such as changes of food, changes of weather, or other known 

 causes. There appears to be no relation between the weather conditions 

 and the variations. Last year cold weather appeared to have a 

 tendency to decrease slightly the quality and quantity of the milk, and 

 warm weather to increase both slightly; much greater variations, 

 however, were found in the course of the experiment, for which no such 

 explanation could be given. In the present experiments the changes 

 in the food were extremely small, and during the greater portion of 

 the time no change at all was made. 



Table I., 



Showing variations of the fat-content. 



Herd. 



Samples. 



Highest 

 Per Cent. 



Lowest 

 Per Cent. 



Range of 

 Variation. 





Morning 

 Evening 

 All samples 



3-5 

 3"8 



3* 



29 

 3*2 

 2"9 



0 6 per cent. 

 o'6 ,, 

 o"9 



'{ 



Morning 

 Evening 

 All. samples 



3-6 

 3-8 



3'8 



2'8 

 3'2 



2-8 



o*8 per cent. 



0- 6 „ 



1- o 





Morning 

 Evening 

 All samples 



3-6 

 4*4 

 4 "4 



27 

 30 

 27 



o'9 per cent, 

 i'4 „ 

 VI „ 





Morning 

 Evening 

 All samples 



4*5 

 47 

 47 



3 3 

 3'3 



1 *2 per cent. 



14 '-' : ^3H 



In the case of three of the herds samples of the mixed milk some- 

 times contained less than 3 per cent, of fat ; out of the seventeen weekly 

 tests made in 1909 the number of times on which this occurred was as 



