286 



MILK 



on the effect of vacuum cleaning of cows so far have not shown a 

 distinct advantage. Harding, Ruehle, Wilson, and Smith have 

 made a number of tests which seem to show that when the vacuum 

 is relatively high, machine cleaning is as effective as hand clean- 

 ing, but at low pressure hand cleaning gives better results than 

 machine cleaning. 



Whatever means of cleaning animals are employed, the germ 

 content in the millc will always be lower when cows are kept clean 

 than when they are poorly cared for, other things being equal. 



2. Dust from the Stable Air. — The air of the stable usuallj- 

 contains dust in amounts proportionate to the care devoted to 

 keeping the stable clean. The construction of the stable is of 

 importance, inasmuch as the practicabihty of keeping it clean and 



Fig. 93. — A sanitary bam, clean and whitewashed. (Fraser, Bull. No. 92, 

 Univ. of III Agri. Exp. Sta.) 



the amount of work required to accomplish this object depend in 

 large measure on suitable construction. Ledges, exposed rafters, 

 sharp corners, braces, and rough supports should be avoided as 

 much as possible, since they give opportunity for dirt and cob- 

 webs to gather. Location of the stable on elevated land is to be 

 highly recommended, since drainage is facihtated thereby. 



The floor of the stable should be made of non-absorbent mate^^ 

 rial,. concrete being the most suitable. Concrete is not only ad- 

 vantageous because of its lack of permeability to liquids that are 

 usually heavily contaminated, but because it can be moistened 

 with water in order to prevent dust from rising (Figs. 93-95). 



The walls and ceiling must also be tight so as to avoid crevices 

 in which dust can accumulate. The surface of the walls and ceil- 



