28 Scientific Proceedings, Royal Dublin SociettJ. 



In the experimental work so far carried out, one important question has 

 not been answered. No experimenter has definitely determined the maxi- 

 mum daily increase bullocks are capable of making and the food necessary 

 to produce it, and farmers, being more immediately concerned, perhaps, with 

 the mere conversion of straw and roots into manure, have not asked the 

 question. The need for knowing the possible maximum increase may not 

 be obvious, but it is none the less important, for, since a certain portion of 

 his daily ration — roughly, about a third in the case of a fattening bullock, 

 and frequently nearly the whole, sometimes more, in that of a store bullock 



is required for mere maintenance of life, while the rest goes towards 



increase in live weight, it is clear that the bullock which fattens the quickest, 

 and so shortens the expenditure in mere maintenance, requires, over all, the 

 smallest amount of food for the beef produced. 



Missing this question, experimenters, as a rule, have usually sought to 

 deal merely with questions of the moment which occurred to farmers in 

 their customary practice. When turnips came into use, but before the 

 introduction of concentrates, the first systematic experiments (Thaer's) were 

 devised to find how many turnips should be substituted for the hay with- 

 drawn from the old ration of hay alone and have the bullocks continue in 

 the old condition. In time, it was found that too many turnips could be 

 fed, but nobody found what might be called the limit of safety. Had some 

 one determined the optimum proportions of straw, or hay, or both, with 

 turnips, it is possible that, when concentrates were introduced, experi- 

 menters might have tried to determine how much extra live weight was 

 produced by the addition of concentrates, and then raised the question : 

 what is the possible live weight increase ? British experimenters have 

 followed no clear policy, and so no crucial question has been sufficiently 

 investigated to become the starting-point for a successor. For the most 

 part, the experiments have been mere trials of varying quantities of roots or 

 straw, or of one or more food-stuffs against each other. 



By using the Scandinavian system of food-units, it may be possible, 

 however, to make a great part of the recorded British experiments comple- 

 mentary to each other, and to draw some general conclusions which may be 

 approximately accurate and, so far, useful. This may be done by calculating 

 the food-units contained in the rations and plotting them against the daily 

 increases each ration produced, as in the diagram (Plate IV.). To bring out 

 the point that the food consumed rises with their weights, the experimental 

 animals have been divided into groups of ascending weights and the 

 plottings for each group set out in separate sets. The weights are the 

 averages during the experimental periods. 



