191 1.] Concentrated Feeding-stuffs. 



295 



object of such admixture is at once apparent, for linseed cake 

 and cereal meals cost, roughly, from £6 to ^"io per ton, 

 whereas the price of genuine linseed is frequently about £20 

 per ton. The risk would be obviated by purchasing whole 

 linseed and having it ground at home, but the objection to 

 this is the difficulty of grinding owing to the linseed clogging 

 the grist-mill. 



Cakes are the pressed residues obtained in the extraction 

 of oils from various seeds and nuts, e.g., linseed, cottonseed, 

 rapeseed, cocoanuts, earth nuts, &c. Apart from mixtures 

 of materials that are specially compressed into cakes and sold 

 under the description of mixed or compound cakes or feeding 

 cakes, only four distinct kinds of oil-cakes are commonly used 

 in this country, viz., linseed cake, decorticated cotton cake, 

 undecorticated cotton cake, and soy bean cake. To a limited 

 extent, cocoanut cake and rape cake are also used. 



Regarded as a group of feeding-stuffs, cakes may be con- 

 sidered as highly concentrated albuminoid or flesh-forming 

 foods. For this reason, when consumed with a diet of straw 

 and roots, which are essentially carbohydrate or heat- 

 producing foods, they supply the feeding material that is 

 most deficient. Where the straw is replaced by hay the con- 

 centrated food need not be so highly albuminoid in character, 

 and, in that case, cereal grains may sometimes be economi- 

 cally substituted, partially or entirely, for cake. 



Next to albuminoids the most important ingredient in cake 

 is oil, and the price of certain sorts of cake is often largely 

 controlled by the percentage of oil present. That the fatten- 

 ing capabilities of a cake are to some extent due to the oil 

 there can be no doubt, as experiments upon sheep in this 

 country have clearly shown the superiority of cakes rich in 

 oil over others poor in this ingredient; but farmers should 

 be careful that the extra percentage of oil in a cake is not 

 purchased at too high a rate. It is well known that oil is not 

 equally valuable from whatever source it is derived, and it is 

 important that all the oil in a cake should be the natural 

 product of the seed from which the cake takes its name. 

 Thus in a linseed cake the whole of the oil present should be 

 linseed oil. 



Any substitution of mineral oils for vegetable oils must be 



