366 
Journal of Agricultural Research 
Vol. XXI, No. 5 
Table XX .—Maximum rate of air flow possible if a temperature difference of 50 ° F. is 
to be maintained 
Species. 
Average 
live 
weight. 
Air flow 
per day 
per head. 
Air flow 
per hour 
per head. 
Cows. 
Pounds. 
1,075 
1,250 
280 
9 1 
Cubic feet. 
60,530 
4 °, 459 
13.453 
5. 82 5 
Cubic feet. 
2,522 
i, 686 
561 
243 
Horses... 
Swine. 
Sheep. 
The results recorded in Table XX are notably lower than the minimum 
air flow computed in Table XVII as necessary to maintain the carbon- 
dioxid content of the stable air at 0.167 P er cent an d s till further below 
the rate of air flow recommended by King. In other words (at least in 
the specific cases used as examples) it will be necessary in severe weather 
to restrict the ventilation in order to conserve heat and maintain a desir¬ 
able stable temperature, and consequently the stable air will fall below 
King’s standard of purity—namely, 0.167 per cent of carbon dioxid. 
The writers are not acquainted with any investigations upon the effects 
of a higher percentage of carbon dioxid upon animals during long periods, 
but in experiments with the respiration calorimeter this limit has fre¬ 
quently been exceeded in 2-day trials with no obvious ill effects. 
Evidently there is a certain degree of discrepancy between King’s re¬ 
quirements and the results of our computations. As has been mentioned 
on previous pages, the amount of carbon dioxid produced by animals is 
approximately proportional to their heat production, so that the rate of 
ventilation should also be approximately proportional to the heat pro¬ 
duction in order to maintain any desired standard or purity in the air of 
the stable. It is true that the heat production of animals may vary 
widely, but to the extent to which the examples we have used may be 
regarded as typical it appears that the accepted ventilation requirements 
for the different species are not proportional to their heat production. 
Taking the values for cows as unity, the relative computed heat produc¬ 
tion and King’s relative ventilation requirements are approximately as 
follows: 
Animal. 
Relative 
heat pro¬ 
duction. 
Relative 
air move¬ 
ment. 
I. 0 
I. O 
Heavy horses. 
.8 
I. 2 
Swine. 
. 2 
. 4 
Sheep. 
. I 
1 
. -2 
O 
Too much stress should not be laid on these differences, in view of the 
paucity of data for other species than cattle, but they indicate clearly 
the need for further fundamental investigation. 
