162 J ou null of Agriculture, Vicforid. [10 March, 1916. 



- THE PRACTICAL ECONOMY OF SKIM MILK. 



By J. M . Kerr, Senior Dairy Supervisor. 



Every gallon of cream sold, leaves on tlie farm about nine times its 

 own bulk of separated milk to be turned to other account. The use 

 to which skim milk is most commonly put is conversion into bacon by 

 feeding to pigs ; but it is rare indeed to find it being used as economically 

 as it might be in the process. Thi& is mainly due to a defective under- 

 standing of its limitations, in which case the discredit which is so often 

 visited on the skim milk should really attach to its owner. Properly 

 understood, and properly utilized, skim milk has a value which no 

 ordinary dairyman can afford to despise. 



Whep.e Fat's Common Virtue does not Apply. 



In utilizing skim milk, it should never be forgotten that the natural 

 fat is missing, and that, in consequence, skim milk alone is a one-sided 

 food for any animal. As it happens, skim milk retains the most 

 valuable food ingredients, the loss of fat notwithstanding. From the 

 bacon-curer's point of view, fat is the ingredient which can best be 

 spared. In animal nutrition, fat shares with starch the function of 

 generating the requisite heat and energy, though of the two, fat is 

 much the more efficient for the purpose. This gives fat a very high 

 value in most feeding operations, but feeding for bacon production is 

 the exception. 



An animal warmly-kept, and at rest — as a fattening pig should be^ — 

 need consume but little heat-producing (carbohydrate) ingredient to 

 satisfy all its needs in that ^^articular direction. If these needs be much 

 exceeded, nature, being unable to utilize the surplus heat and energy, 

 conserves them in the system, in the form of fatty tissue, to a degree 

 inconsistent with the popular taste in bacon. It not only means an exces- 

 sive proportion of fat to lean, but, if the diet be too fatty, the bacon 

 so produced is poor also in colour, flavour, and keeping quality. For this 

 reason, the heat and energy supply of a pig may well be entrusted to 

 tie less active carbohydrate — starch — a food ingredient which exists to 

 superfluous extent in most foodstuffs commonly available on the farm. 



Skim Milk an Unbalanced Ration. 



A food to be complete must possess two distinct groups of ingredients. 

 One group is represented by fat and starch, which have a common 

 function — which, in the case of a restful, comfortable pig, might be 

 called fat formation ; the other is protein, which has a different function, 

 viz., mainly flesh formation. In a perfectly-balanced diet, these two 

 classes of food must exist in a certain ratio to one another — the nutritive 

 ratio. Any departure from this relation, one way or the other, is a 

 detriment. As the solid portion of whole milk contains the respective 

 food groups in just ideal proportion for a growing animal, neither 

 part can be depleted without leaving the other superabundant in con- 

 sequence. It is because the butter-fat is missing that the remaining 

 solids contain such a high percentage of protein — in fact too much 

 protein. 



The High Protein Content Particularly Valuable. 



This is a rare virtue in foodstuffs, and the dairy farmer who fails to 

 appreciate its significance in animal feeding does not know his business. 



