I'ebruary. 19"^!^ agricultural experimknts r.)28 17 



THE BASAL METABOLISM OF SHEEP 



The l)asal energy requirements of shee]) have Iteen stiuhed by E. G. 

 Kitzman during the past year in co-operation with Dr. F. (j. Benedict of 

 tlie Carnegie Institution of Washington, D. C \ ery htt'e definite informa- 

 tion on this subject has been availal)Ie hitherto with this important class of 

 farm Hvestock. Since this laboratory has established the fact that the 

 basal, or maintenance, requirements for energy of adult Ijeef steers is 1.300 

 calories per square meter of body surface instead of about 000 calories as 

 was formerly assumed, it has become a problem of economic as well as of 

 physiological interest to determine the definite demands of sheep for this 

 purijose. 



Over 100 respiration experiments have now been carried out on sheep 

 during the past seven years, and the results are being prepared for 

 ])ublication. 



A new type of respiration chamber. es]>ecia]ly designed for this investi- 

 gation by Dr. Benedict, has been used. It is believed to be the simplest 

 form of apparatus so far conceived for such studies, and its use promises 

 to ofifer a great advance in indirect calorimetry. (Adams Fund.) 



FASHIONS IN WOOL COVERING UNPROFITABLE 



Attempts to breed sheep with points of fashion strongly in mind quite 

 frequently have a negative effect on the animal produced, finds E. G. Ritz- 

 man from his sheep breeding studies. 



In registered purebred sheep definite types or patterns of wool covering- 

 over face, ears and legs peculiar to any one breed must form the index 

 of homogeneity of visible traits by which breeds are distinguished from 

 each other. Most of these breed characteristics have of course a utilitv 

 basis which is exhibited in the improvement of conformation of function ; 



Wool coverings on the face like the above are only a point of fashion, and 

 breeding for such characteristics is at the expense of other more important factors 



but present breed standards also require characteristics which have no 

 utility value but which supposedly enhance the appearance, and may, there- 

 fore, be classed merely as points of fashion. Among these latter, wool 

 covering over face, ears and legs is an outstanding example. It has been 

 found that all breeds are genetically more or less heterozygous with regard 

 to these individual traits so that selection for mating with the improvement 

 of any one characteristic in view is often accomplished at the expense of 

 some other trait, particularly when there is no correlation. Thus the prob- 

 lem of maintaining a high standard of perfection in a group of traits 



