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



degrees, a pair of small chains holding them suspended laterall}^, to which 

 position they drop of their own weight. If the bumpers were of a fixed 

 instead of hinged type, the animal would probably have great difficulty in 

 rising from the lying position, since they would form a rigid obstruction. 

 With the hinged type the animal, on rising, simply pushes one or both of 

 them up without resistance and then they drop down again to the lateral 

 position of their own weight. 



An adjustable feed box and stanchion were provided by which the length 

 of the stall could be varied to conform to different sized animals so that the 

 hind feet are always about 6 inches from the floor opening or grid when the 

 animal stands in a normal position. Wastage to the rear is prevented by 

 a removable splashboard. 



Excreta Collecting Apparatus 



The special feature connected with these metabolism stalls is the ap- 

 paratus for the separate collection of feces and urine from cows. The pri- 

 mary object in developing this apparatus has been to do away with all the 

 usual harness used for such purpose, in order to relieve cows of encum- 

 brances which tend to produce abnormal conditions. Incidentally the 

 employment of this apparatus has resulted in an improvement in the 

 sanitary conditions of the stalls and in a saving of labor. Furthermore, it 

 enables the separate collection of urine and of feces continuously for the 

 whole experimental year which is, of course, preferable to the short periods 

 of two or three weeks customary when much paraphernalia must be at- 

 tached to the animal for separate collections. 



The apparatus for collecting urine and feces from cows in separate re- 

 ceptacles is located in the basement immediately under the grid of the 

 metabohsm stall. It consists of a framework (as shown in Plate 7 and in 

 Fig. 6) made of wood which carries a large metal pan. Within this pan 

 there is a belt 20" wide, mounted on two wooden rollers, one 8" in diameter 

 and the other 6 inches in diameter. The roller on the end toward the 

 receptacle which receives the feces is the larger in diameter and it is 

 set somewhat higher so that the top surface of the belt on which the 

 excreta drop is on an incline and moving uphill. The chute leading 

 down from the stalls above it directs the excreta to the center of the belt, 

 which latter moves very slowly, giving the urine time to drain off the 

 sides and back into the pan, from which it drains into the carboy below, 

 while the feces (which remain stationary on the belt) move upgrade 

 and thus are carried over into the receptacle used for this purpose. 



The principle of this apparatus is based on the fact that cows do not 

 urinate and defecate at the same time, or even very nearly the same time, 

 and hence there is httle chance of mixing of feces and urine while they are 

 on the belt. The rate of movement of the belt must be slow enough to 

 permit urine to drain off before it is carried over into the receptacle for 

 feces. Although small amounts of feces do occasionally work down the 

 sides of the belt into the urine pan, these are recovered by a strainer in 

 the cup-shaped receptacle at the bottom. Any feces collecting in this 

 receptacle are, of course, removed and weighed to obtain the correct weight 

 of total feces, but the material thus collected is discarded after weighing. 



The question of contamination of urine by these fragments of feces in 

 the draining pan has been raised. This has not been checked by analytical 



