Variations in the Composition of Milk 

 and their Probable Causes. 



Published December, 1903. 



BY DOUGLAS A. GILCHEJST. 



An inquiry into the variations in the composition of milk 

 by the Agricultural Department of the Durham College of 

 Science* has been in progress since January 1st, 1903. At the 

 request of the Northumberland County Council, the College 

 undertook to make these investigations of a more thorough 

 character, and to extend this work in that county. 



A large number of samples of milk of individual cows and 

 of mixed milk have been collected from different farms, and 

 the amounts of butter fat and of solids not fat contained 

 therein have been estimated. The breed of the cows, the times 

 of milking, the weather conditions, the temperature outside 

 and inside the cowsheds, and the daily rations fed to the cows, 

 have all been noted. Mr. James McLaren, Offerton Hall, and 

 Mr. Charles Marshall, Broomhaugh, both placed their herds 

 at the disposal of the College, and samples of milk from 

 individual cows and from the mixed milk of these herds have 

 been taken fortnightly and tested at the College. Samples 

 have also been taken and tested from cows on the Duke of 

 Northumberland's Home Farm, Alnwick, and from the herd of 

 Mr. J. Swann, Lookout Farm, Seaton Delaval. As changes 

 in the composition of milk of individual cows occur very 

 quickly, the milk of one cow has been regularly tested at 

 Cockle Park during the greater part of 1903, so that their 

 extent might be noted. 



* Now Armstrong College. 



