February, 1930J agricultural experiments 1929 21 



ciated with the multi-nipple trait the majority of the oflfsprins possess 

 only two functional nipples. 80 far six female offspring having four 

 functional nipples have been obtained. 



Further data obtained on the effect of crossing coarse wool and fine 

 wool breeds support the earlier conclusions that when extremes are crossed 

 there results dominance of neither fine nor coarse wool. In the recent 

 crosses somewhat greater extremes in parent stock were used than hereto- 

 fore, one-half bloods being crossed with quarter bloods. It has become 

 apparent that attempts to improve the quality of wool require constant 

 selection and careful weeding out of undesirable characters if the inter- 

 mediate characters are to become stabilized as blends which will be trans- 

 mitted as such. 



All sheep breeding experiments are in charge of E. G. Ritzman. 

 {Adams Fund.) 



METABOLISM OF MILCH COWS 



Following ten years of study with dry cows and steers a stud}' of the 

 insensible perspiration of milch cows, or daily loss in weight due to ex- 

 cretion of carbon and water vapor through the lungs and skin, was begun 

 in 1928 by E. G. Ritzman in cooperation with Dr. Francis G. Benedict, 

 director of the nutrition laboratory of the Carnegie Institution of Wash- 

 ington. 



Insensible perspiration is significant in two respects — its probable cor- 

 relation to general metabolism which alread}^ has been found to exist in 

 humans, and its value in establishing the water balance of animals under 

 different conditions of feeding. 



Results indicate that insensible perspiration is the safety valve by 

 which the animal eliminates excess heat under high pressure of metab- 

 olism. Daily changes in the amount of feed consumed, in humidity, and 

 in environmental temperature invariably reacted on the insensible per- 

 spiration without a corresponding change in the milk flow. 



The cost of digestion in terms of energy consumed was measured for two 

 dry, farrow, Holstein cows both of which had been record producers. 

 The cost of digestion, as represented by the difference in metabolism on 

 full feed and the second fast day, equalled 55 per cent of the fasting metab- 

 olism in the case of one animal and 60 per cent in the case of the other. 

 The difference was largely due to a difference in basal requirement, the 

 actual cost of digestion measured in calories being almost identical — ■ 

 4,030 and 4,860. 



The rations used were in sufficient amount to supply maintenance, as 

 follows: 5 kgs. hay; 2 kgs. beet pulp; and 1 kg. linseed oil meal. (Purnell 

 Fund.) 



ELECTRIC HOUSEHOLD REFRIGERATION 



On six of the seven experimental farms in the New England rural elec- 

 trification project, electric household refrigeration was studied by W. T. 

 Ackerman. The refrigerator proved one of the most desirable pieces of 

 electrical equipment for farm homes in the opinion of all the farmers and 

 their wives. 



Two general types of equipment were studied. One type was in com- 



