THE MAmTENANC!E RATION OF OXEN AND 

 THE STARCH EQUIVALENT THEORY. 



By E. T. HALNAN, M.A. 



{Animal Nutrition Institute, Cambridge.) 



Within recent years, Kellner's system of starch equivalents has 

 received much criticism from various quarters, and its vahie as a 

 practical feeding system has been called into question. That the system 

 is far from perfect in its working is universally admitted, and the 

 recent work of W. Bruce^ with oxen has done much to emphasise this 

 fact. In a series of practical feeding trials with oxen, Bruce obtained 

 results contrary to those expected from the theoretical consideration 

 of the Kellner system of starch equivalents, and largely on account 

 of this work, and partly on account of the demonstration of the import- 

 ance of the part played by certain unknown chemical compounds 

 in the normal metabolism of animals, many workers have been led to 

 suggest a total abolition of the Kellner system. It is, however, incon- 

 ceivable to the author that a system based on 30 years continuous 

 research upon feeding problems, should be condemned without the 

 fullest possible enquiry. Furthermore it is supported by many experi- 

 mental results. In a critical comparison of the values of certain foods 

 for milk production theoretically computed by the Kellner system, 

 Crowther- has shown that the residts obtained wth one exception 

 agree very well with those obtained in actual feeding practice. More- 

 over, mth regard to the food deficiency factors which play such an 

 important role in the normal metabolism of animals, Hopkins^ has 

 shown that those factors are hardly likely to be missing in normal 



* Bruce. " Cattle Feeding Experiments," Edinburgh and E. of Scot. Coll. of Ag. Bejiort, 

 27. 



- Crowther, Science Progress, 7, p. 436 



" Hopkins, Journ. of Pliys. 1912, 44, p. 425. 



