ANIMAL NUTRITION DISCUSSION AT DUNDEE 415 



tion of animals arises from the necessity of working with large 

 numbers; it is this circumstance that gives peculiar value to 

 the experimental work done by Mr. William Bruce, of the 

 Edinburgh and East of Scotland Agricultural College, whose 

 communication was the first taken. 



THE VERDICT OF THE BULLOCK 

 (William Bruce) 



The experiments to which this communication relates were 

 designed to test feeding stuffs and rations as used under the 

 ordinary conditions of farm practice. The object in view was 

 to provide practical guidance for the farmer rather than to 

 deal with any scientific questions with regard to animal nutri- 

 tion. Nevertheless, at least one point has emerged that is 

 closely connected with this subject. 



It may be noted here that a special feature of these experi- 

 ments is the scale on which they have been carried out. With 

 the object of eliminating individual variation and reducing 

 the probable experimental error to a minimum, larger lots 

 of animals were employed than is usual in such work. 

 Besides this, some of the findings have been checked and 

 confirmed by repeating the trials. 



As the experiments extend over eight seasons (1904-12), 

 it is impossible on the present occasion to discuss all the con- 

 clusions arrived at. Two issues which are of both practical and 

 scientific interest have therefore been singled out for discussion. 

 These are : 



(1) The bearing of some of the results on the "starch 

 equivalent " method for the valuation of feeding stuffs. 



(2) A comparison of the value of the feeding stuffs as deter- 

 mined by the experiments. 



The " starch equivalent " method of valuing a feeding stuff 

 consists in analysing the material under consideration and 

 multiplying the analytical results by digestibility co-efficients 

 which have been determined by digestion experiments with 

 the foodstuff in question. The figures so obtained for the 

 several digestible nutrients are then multiplied by their 

 respective energy values, starch being taken as unity. 



The special point of the method lies in the attempt that is 

 then made to deduct from this total energy value a figure 

 27 



