38 



Variations in Milk. 



[APRIL, 



Advantage is taken of the educational facilities afforded by 

 the agricultural shows, and the students not only watch the 

 judging in the ring, but go round the shows under the 

 guidance of an instructor and have the points of the animals 

 explained to them. At the Chicago Live Stock Exhibition 

 prizes are given for the judging of live stock by students 

 (See Journal, May, 1906, p. 103). 



An investigation into the fat-content of milk has been carried 



out in Sweden by Herr Hogstrom in connection with a 



,„ herd of pure-bred and improved Avt- 

 Investigations into the _ . Jl . _ ■ _ . J 



„ . , . shires. Ihe investigation extended over 



Variations in the . , x , . . , 



« * eight vears, and represented results from 



Quality of Milk. 6 ~. , , / 0 , n , x 



393 animals and from 10,439 milk tests. 



It deals with many phases of the question of the variations 



in the quality of milk, and the following is only a very brief 



summary of some of the different points.* 



Monthly Variations. — The average percentage of fat in the 

 milk over the whole period was 3' 68, but the average for 

 each month showed considerable variation. Starting from 

 370 in January, it fell fairly steadily to about 3-50 at the 

 beginning of June, it then began to rise until towards the end 

 of July, when it again reached 370 per cent., and continued to 

 rise till the end of November, when it stood at about 3*83, 

 after which it again declined. 



Effect of Age of Cows.— The richness of the milk is shown 

 to be related to the age of the cows, as the milk over the whole 

 lactation period of 94 three-year-old cows averaged 3*83 per 

 cent, and of 150 four-year-olds 374 per cent. ; thereafter, up to 

 the tenth year there was not much variation and the general 

 average of a large number was 3-67 per cent. In the same 

 way there was not much variation in the quality so long as 

 the yield was fairly normal (400-600 gallons), but with a lower 

 yield the fat- content was high and the reverse with a higher 

 yield. 



Variation during the Lactation Period.— It was found that at 

 the beginning of the first month after calving, the milk averaged 



* Kungl. Landtbruks-Akademiens HandUngar och Tidshift., Nos. 3 and 4, 

 1906; summarised in Mitt, der Deutschen Land.-Gbsellschaft, 24th Nov. and 

 8th Dec, 1906. 



