DAIRY INSPECTION 16r 



done to keep the atmosphere as free from dust as possible. 

 In other stables land plaster is spread in a thin layer on 

 the floor and in the gutter to act as an absorbent. This 

 is especially desirable when the floor is of wood or earth. 

 The use of land plaster also seems to have the effect of 

 reducing the number of flies. Although the inspector 

 cannot be present during all of these operations, he can 

 make a fairly accurate estimate of how thoroughly the 

 work is done by observing the condition of the stable 

 at the time of his visit. Dirt which has been permitted 

 to remain for some time can be easily distinguished from 

 fresh dirt. The wall in the rear of the cows and the 

 corners formed where the walls, posts, and stall divisions 

 join the floor should be especially examined. The pres- 

 ence of cobwebs on the walls, ceiling, or other places is 

 an evidence of infrequent sweeping. 



Flies. The presence of flies in large numbers in and about 

 a cow stable is objectionable for several reasons. The flies 

 worry the cows and reduce the milk production, while the move- 

 ments of the cows in their efforts to protect themselves from 

 the insects interfere with milking and are also likely to dislodge 

 dirt from the body of the cow ; some of this dirt may fall into 

 the milk pail. The common house-fly (Muse a domes tica) is 

 especially objectionable. It feeds upon all kinds of organic 

 matter, including human excrement, and becomes contaminated 

 with numerous bacteria. A single fly may carry over a million 

 germs on the surface of its body. When it feeds upon milk 

 or crawls or falls into milk vessels, many of these bacteria are 

 transferred to the milk. Typhoid bacilli may be carried from 

 infected fecal matter to milk in this way. The small, black cow- 

 fly or horn-fly (Hematobia serrata, Lyperosia irritans L.) and 

 the stable-fly or biting-fly (Stomoxys calcitraws) disturb the 

 cow more than the house-fly, because they are biting or blood- 

 sucking insects; but they do not as a rule invade the milk 

 vessels or the milk. 

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