28 



The following figures give the approximate compositions of the milk 

 of different breeds : — 



Total Solids* 

 (Per Cent). 



Fat 

 (Per Cent). 



Solids not 



Fat 

 (Per Cent). 



Average milk, 



Holstein, 



Ayrshire, 



Shorthorn, 



Devon, . 



Jersey, . 



Guernsey, 



13.0 

 11.8 

 12.5 

 12.9 

 13.4 

 14.7 

 14.7 



4.0 

 3.2 

 3.7 

 3.8 

 4.4 

 5.0 

 5.0 



9.0 

 8.6 

 8.8 

 9.1 

 9.0 

 9.7 

 9.7 



* Containing milk sugar, curd and ash. 



While the above figures can be taken as types, they do not mean that 

 every cow of a distinct breed will give milk of the above composition. 

 In fact, a great many Jerseys produce milk with 4 per cent of fat, and 

 families and individual cows of Holstein breed yield milk as rich as do 

 many Jerseys or Guernseys. 



Varialiojis m the quality of milk are due to a variety of causes. 



The substance showing the greatest variation is the fat, while those 

 remaining more nearly constant are the milk sugar and the ash. The 

 milk is generally poorest in quality, i. e , contains the most water, for 

 the first few weeks after calving, and grows gradually richer till within 

 a few months before calving. As the cow becomes dry the solid matter 

 increases quite rapidly. With some cows the composition of the milk 

 remains nearly constant from the fourth week until the end of the sixth 

 month after calving, while with others a gradual increase in richness is 

 observed. Morning milk is quite frequently poorer in fat than evening's 

 milk. This is lai'gely due to the unequal periods between milkings. 

 As a rule, the shorter the time between milkings the richer the milk in 

 fat and vice versa. Cows milked three or four times daily, produce milk 

 richer in fat than those milked but twice. The composition of a single 

 cow's milk will vary from day to day. Such variations are to be attrib- 

 uted to effects of the weather conditions, environment, change of food, 

 etc. 



The quality of milk from different portions of the same milking dif- 

 fers widely. The first part of the milk drawn is poorest in fat and the 

 last richest. 



Feed has no marked effect on the composition of milk. This state- 

 ment, however, needs to be qualified. An animal that is poorly nourished^ 

 by receiving insufficient food or food containing an excess of carbo- 

 hydrates and a lack of protein, will give milk of somewhat poorer 

 quality than animals normally fed. An excess of fat in the food will 

 tend to increase the fat in the milk, providing the animal is able to 

 digest and assimilate the fat. Feed appears to aftect, to an extent, the 

 quality of the fat in the milk. Thus gluten and linseed meals tend to make 

 a softer oily fat, while cotton-seed meal produces a hard fat. The other 



