DISEASES OF ANIMALS 



93 



otherwise the matter could not be con- 

 trolled at all. Where air can leak in 

 through various cracks this is sufficient 

 to interfere with the operation of an 

 artificial system of ventilation. 



Ventilation important — The princi- 

 ples upon which a scientific system of 

 ventilation is based are the necessity of 



I }L45lL_jt5l 



2L& 



Fig. 52 CROSS SECTION OF THE WISCON- 

 SIN STATION BARN SHOWING SYSTEM OF 

 VENTILATION DEVISED BY PROFESSOR KING 



furnishing as large amounts of air as 

 possible without reducing the tempera- 

 ture of the stable in winter unnecessa- 

 rily. Obviously the air which rises to 

 the roof of the stable is warmer than 

 that upon the floor. Much of the heat 

 generated by the animal body is, there- 

 fore, lost by removing the air near the 

 roof. Again, this air does not contain 

 the impurities which it is desirable to 

 remove, since they are for the most 

 part heavy and remain nearer the floor 

 of the stable. The best systems of ven- 

 tilation, therefore, provide for taking 

 the foul air from near the floor and dis- 

 charging it to the outside with as little 

 loss of warm air as possible. The ven- 

 tilating system which has been devised 



and worked out by King operates very 

 successfully in all moderate climates in 

 winter, but, according to some Canadian 

 experiments, is not very successful in 

 the extreme cold weather which prevails 

 in Canada during midwinter. 



Recent experiments in Minnesota have 

 shown that steers in the process of fat- 

 tening appear to thrive well and re- 

 main comfortable when confined in box 

 stalls as tight as they can be made, be- 

 ing removed for a short time once a 

 week. It is perfectly obvious, therefore, 

 that ventilation is a matter which may 

 be overestimated, in and of itself, under 

 conditions which are otherwise sanitary. 

 If, however, an infectious disease pre- 

 vails on any given premises it is much 

 more necessary to give heed to proper 

 ventilation, since otherwise, the disease 

 will spread and affect animals more ex- 

 tensively than would be the case if large 

 quantities of good air were provided. 



Fig. 53 HINGED VALVE FOR VENTILATING 



STABLE 



Care of yards — In safeguarding the 

 health' of animals another important 

 point remains in connection with the 

 care of yards. Quite too often animals 

 are allowed to stand in wet, unspeakably 

 filthy yards. In the case of dairy cows, 

 the animals become so filthy that it is 

 practically impossible to obtain clean 

 milk from them and other animals be- 



