72 



MANUAL OF MILK PRODUCTS 



I JERSEY j I SHORTHORN j f AYRSH , RE \ f H0LSTE)N \ 



Fig. 3. — Relative size of fat globules in milk, 

 breed. Lower, as influenced by stage of lactation. 

 (2) fifth 4-week period ; (3) ninth 4-week period ; (4) 



Upper, as influenced by 

 (1) First 4-week period ; 

 thirteenth 4-week period. 



Influence of age of cows on number and size of fat globules. 



Woll * studied the milk of twelve cows to determine the effect 

 of age on the number and size of the fat globules. His work 

 covered a period of three years, samples being taken at the be- 

 ginning and end of the lactation period. The following table 

 gives the data thus obtained : 



Effect of Age of Cows on Fat Globules in Milk 



At 



Beginning of Lactation Period 



Three-year Series 







Year 



No. of 

 Glob. 



Rel. Size 



Milk, Lb. 



Fat 

 Per Cent 



Day in 

 Milk 



First 



Second 



Third 



164 

 155 

 137 



293 

 302 

 357 



22.85 

 24.17 



24.88 



4.38 



4.29 

 4.29 



31 

 15 

 14 



At End of Lactation Period 

 Three-year Series 



First 



Second 



Third ..... 



311 

 369 

 334 



179 

 119 

 147 



6.77 



12.14 



6.92 



4.96 

 4.52 

 4.57 



300 

 251 

 316 



1 Wis. Report, 1894, pp. 237-238. 



