MANUAL OP CATTLE-FEEDING. 47 



Other plants, contain from 10 to 40 per cent, of oil, acemw- 

 p<inied generally In a eoiiHideuihle quantity of protein. 



The oil fornib an article t)f connneree, and h connnoiily 

 obtained by biniply pressing the beeds. 



By this procobS, however, it is impossible to separate all 

 the fat, and in the residue of the manufacture — oil cake, 

 rape cake, cotton-seed cake, etc. — there is left a consider- 

 able amount (S to 12 per cent.) of oil, together with nearly 

 all the albuminoids, and hence, owhig to the importance of 

 both classes of nutrients, these residues constitute most 

 valuable fodder materials. 



Sometimes the oil is extracted by means of solution in 

 bisulphide of carbon instead of by pressing. In this ease 

 the residue is valuable chiefly on account of its albuminoids, 

 the fat content being reduced to from 2 to 4 per cent. 



Value. — ^In the ordinary fodder of our domestic animals 

 fat plays a rather subordinate part, but in rapid fattening it 

 is a most important aid, thougli, as we shall see, it is by 

 no means the sole source of fat to the animal body. In 

 addition to its direct imtritive effect, it also aids in the 

 digestion and resorption of the important albuminoids. 



I 4 iNOEaANIC N'UTEEENTS. 



These comprise the substances found in the ashes of 

 plants — the so-called inorganic or mineral constituents. 

 The need of these in the animal organism and |heir f imc- 

 tions, so far as known, have been already sufficiently 

 spoken of in Chapter I. In all ordinary cases a ration 

 which contains sufficient organic nutrients will also contain 

 an abundance of the inorganic, so that commonly no special 

 consideration of the quantity of the latter is necessary, with 

 the exception of common salt, which, for reasons already 



