Feb., 1925] PROGRESS OF AGRICULTURAL EXPERIMENTS 11 



The tremendous stimulus that a heavy energy intake exerts on physical and 

 vital activities suggests the advisability of limiting physical exercise as a matter 

 of material economy in feeding. 



No significant differences were observed in thoroughness of digestion of either 

 protein or energy on different feed levels or between different individuals, as is 

 so commonly believed to exist. The efficiency of rations which varied in 

 quantity depended rather on the capacity of the individual to make an eco- 

 nomic use of the digested food material. 



An exhaustive report on fasting metabolism of steers is now being prepared. 

 This will be issued as a monograph of the Nutrition Laboratory of the Carnegie 

 Institution of Washington sometime during the coming year. 



Some improvements have been added to the respiration chamber this year 

 which permit of feeding and of collection of feces and ui'ine during a respiration 

 experiment. This will be particularly important in carrying on experiments of 

 24-hours' duration and over and in the study of the effect that ingestion of feed 

 has on stimulating metabohsm. 



Sheep Breeding Experiment. 



The Station flock now consists of three distinct groups of sheep of entirely 

 different breeding. 



One group represents the selected stock from the second and third gen- 

 eration of the inbred {i.e., Mendelized) hybrids with Southdown-Rambouillet 

 foundation. The members of this flock are very uniform in size, conforma- 

 tion and wooling quahties. They are low set, compact and of good mutton 

 t^-pe. Furthermore, they produce good lambs for market as shown by the fact 

 that their lambs at four months of age averaged 74.7 pounds in weight and sold 

 for $9.00 per head on the open market. Their wool also is uniform in quality, 

 since all the wool is graded in one-half blood staple or combing class and sold . 

 for top price on a competitive market. In other words, they do meet the two 

 essential qualifications of producing to a satisfactory degree an early maturing 

 market lamb and a desirable type of fleece. 



The second group consists of a Rambouillet ram and 18 purebred Oxford 

 ewes together with 17 head of Fi female offspring. The Oxford blood has been 

 introduced here for the purpose of increasing fecundity and milk yield of ewes, 

 and to add somewhat to length of staple in wool. 



The Fi offspring which have so far been obtained are early maturing and 

 produce an excellent quality of wool, but selections on basis of milk yield and 

 fecundity will be made in the F2 generation. If the latter are satisfactory they 

 will be eventually merged with the Southdown-Rambouillet group. 



In addition to the ram and five ewes of multi-nippled sheep received from the 

 estate of Dr. Alexander Graham Bell last year, the estate has turned over to 

 this Station eight more ewes. 



These eight ewes were selected on the basis of combining not less than four 

 functional nipples with high-twinning tendency, thus transferring to this Station 

 the further perpetuation of Dr. Bell's achievement. 



The work is conducted by E. G. Ritzman and is carried on in co-operation 

 with Dr. C. B. Davenport of the Carnegie Institution of Washington. 



