10 N. H. AGR. EXPERIMENT STATION [Bulletin 208 



record to help establish the true basal metabolism under varying conditions 

 of feeding. In fact until this is finally established, the whole mass of feed- 

 ing experiments and teachings will still be open to great errors; and feeding 

 standards may be subject to a certain measure of revision as they have been 

 in the past. 



From its beginning the main general objective of E. G. Ritzman (Animal 

 Husbandry) and Dr. F. G. Benedict, director of the Nutrition Laboratory 

 of the Carnegie Institution of Washington, who work in cooperation on 

 this project, has been : (1) a study of the nitrogen balance and basal metabo- 

 lism on various planes of nutrition, and (2) the development of improved 

 and simplified methods and technique for studying basal metabolism. 



An illustration of the effect which this work may have on economic stock 

 feeding may be worth while. It has been generally accepted as a fact that 

 animals digest food less thoroughly when fed heavy rations than on a lower 

 feed level, but our investigations conducted under the most carefully con- 

 trolled conditions indicate that in normally healthy animals the complete- 

 ness with which a feed is digested is not influenced by the quantity con- 

 sumed. 



A technical treatise covering the first two years' work on the physiology 



of basal metabolism under maintenance, prolonged sub-maintenance, and 

 heavy fattening rations has been prepared for publication as a monograph 

 of the Nutrition Laboratory of the Carnegie Institution of Washington; 

 and a more abstract treatise in the form of a Station Bulletin will also be 

 prepared. 



During the coming year it is proposed to continue the investigations on 

 basal metabolism along the same general lines as in the past but to empha- 

 size especially (1st) the influence of environmental temperature on metabolism 

 and (2d) improvement of technique by the addition of a gas analysis appara- 

 tus for determining the oxygen consumption by the animal during a respira- 

 tion experiment. This apparatus, designed by the Nutrition Laboratory, 

 has already been successfully tested and its use will place the measurement 

 of the respiratory exchange on a new and decidedly advanced level. 



Sheep Breeding Experiments. 



In developing the new phases of the sheep breeding work Mr. Ritzman 

 has made a rigid selection in the breeding flock. All undesirable individuals 

 of the second and third generation ofif-spring have now been eliminated 

 and those kept are still subject to further culling during the year. These 

 two generations of Mendelized off-spring from Southdowai and Rambouillet 

 ancestors present a remarkable uniformity in a general sense as live stock 

 is judged. In size, character of fleece, and early maturity they have shown 

 much less differentiation than might have been expected. An average 

 flock in any of the standard breeds would hardly present a more uniform 

 appearance. 



In size the F2 and F3 generations average somewhat smaller than Fj. 

 In fact their size is about equal to that of their Southdown ancestry. While 

 not equal to good Southdowns in conformation they are reasonably com- 

 pact and in this respect easily excel the Fi and the RambouUiet. 



