I909-] 



The Construction of Cow Houses. 



55i 



1908 and 1909, in which the air of several cow-houses of 

 medium and large cubic space, but with limited provision 

 for change of air, was compared with others similarly placed, 

 where it was liberal. In those which were freely ventilated, 

 the cubic space per cow varied from 520 to 1,268 cubic ft. 

 In the smaller building, where fully ventilated, the average 

 carbon dioxide in the air, on an average of fortnightly tests 

 by chemical analysis, was io"6 — the minimum being 6'5 and 

 maximum 15*9— per 10,000, the average temperature being 

 slightly under 49 0 F. In almost similar buildings, with 

 the ventilation restricted so as to keep the temperature about 

 6o° F., the carbon dioxide in the air of samples taken at the 

 same time as the other was 29*05 per 10,000, and in some 

 instances was as high as 60, 70, and even 88 per € 0,000 

 volumes. On the average of three tests at one of the farms, 

 the air of the freely ventilated building, with a cubic capacity 

 of 1,130 cubic ft. per cow, contained 9*4 per 10,000, while 

 an adjoining building, with 705 cubic ft. per cow, but with 

 little ventilation, contained 29*03 per 10,000. On two of these 

 farms, at about the same elevation, in the same district, and 

 with much the same exposure, the carbon dioxide in the air of 

 the smaller of the freely ventilated buildings was io*6, while 

 the very large one was 9*4 per 10,000, a difference of only 1*2 

 of carbon dioxide per 10,000, although the one building is 

 fully double the other in capacity per cow. In the buildings 

 with restricted ventilation, the amount of carbon dioxide was 

 identical in both cases, yet the one building had 480 cubic ft. 

 per cow, while the other had 705 cubic ft. In both cases the 

 samples were taken between two and three hours after the 

 buildings were closed for the night. 



In another case, with buildings at a high altitude and 

 exposed situation, but having a large cubic capacity, the 

 dangers and difficulties of attempting to maintain a high 

 temperature in the cow-house are very evident. The ventilated 

 building, with a cubic capacity of 1,268 ft. per cow, and an 

 average temperature of 49 0 F., had on an average of four 

 tests 19*7 of carbon dioxide per 10,000 volumes of air. In 

 the other half of the same building, where the cubic space 

 was 918 cubic ft. per cow, and average temperature 57*5° F., 

 the carbon dioxide in the air on an average of four tests 



