20 



UNIV. OF N. H. AGR. EXPERIMENT STATION [Bulletin 240 



Table II — Total calories of energy metabolized by Holstein cows 



1 No respiration experiments are made on first day after feed reduction. " Represents fasting. 



3 Represents haK-feed. * Same as (3) less 500 gms. linseed oil meal. 



ventilation of the chamber, to stabihze air conditions and rate of venti- 

 lation. At 4.30 P.M. the experiment is begun by deflecting the air current 

 through freshly weighed absorbers for the collection of CO2. At the time 

 when this absoi'ption begins, a sample of air is taken from the chamber to 

 analyze its residual content of carbon dioxide and oxygen. Absorption is 

 continued through one set of absorbers for eight hours, at the end of which 

 another residual sample is taken and the current is deflected through 

 freshly weighed absorbers. This process is continued for 48 hours, 

 during which the animal is fed and watered at regular intervals. Addi- 

 tional observations on general deportment and appearance of the animal, 

 or unusual incidents, are recorded in notes. A typical data sheet showing 

 the nature of the records obtained during an 8-hour period of an experi- 

 ment is reproduced on page 21. Each day is divided into three such peri- 

 ods. Separate data sheets are also used to record: (1) change of body 

 position from standing to lying and vice versa, (2) temperature of cham- 

 ber air every half hour, (3) various steps in gas analysis, and (4) com- 

 putations of the results. 



A graphic record showing the relative activity of the animal throughout 

 the experiment is also obtained by a kymograph clock. 



Respiration Chambers for Sheep 



Plate 5 shows the respiration apparatus which were designed primarily 

 for use with individual sheep and with which about 75 separate respiration 

 experiments have been carried through up to the present time. 



This apparatus (as stated on p. 16) is not provided with means to ab- 

 sorb the carbon dioxide and water, the carbon dioxide and oxygen being 

 determined from the aliquot air sample collected by the pump shown on 

 the table. The carbon dioxide and oxygen content of the sample are then 

 determined with the Carpenter gas analysis apparatus. As this is on the 

 volumetric basis it is, of course, necessary to determine the barometric 

 pressure and also the temperature and degree of moisture in the ventilat- 

 ing current. The chamber for adult sheep consists of three parts: (1) a 

 floor platform provided with groove around the outside which is filled 

 with water to serve as a seal against exchange of air, (2) a crate built of a 

 wooden framework enclosed with one-half-inch mesh wire to accommodate 

 the animal, and (3) a sheet-metal shell (Plate 5), open at the bottom, 



