No 6. 



DEPARTMENT OF AGRICULTURE. 



225 



that needed bv an average person ; and, in order that this amount of 

 fresh air may be siip]ilied regularly without the production of drafts, 

 the amount of space allotted to a cow should be, In proportion to her 

 size, one thousand to twelve hundred cubic feet. ]\[any of the stables 

 in older barns are too low to make it possible to bring about satisfac- 

 tory ventilation, though an undue height of stable is also undesirable. 

 It may be stated that a heiglit of ten to twelve feet is a fair average. 



With proper allotment of space and satisfactory provision for ven- 

 tilation in stables, the purity of the air can be more readily main- 

 tained ; and where pure air j)revails one of the i)rinci])al sources of 

 contamination in the stable, that is, dust, can be largely eliminated, 

 because the smaller the stable and the greater the overcrowding, the 

 greater the amount of dust floating in the air, and this dust finds its 

 way into the milk during the process of milking. 



The dust of stables is a fruitful source of bacteria which cause de- 

 composition and putrefaction in milk. The dust particles and the bac- 

 teria adherent to them are derived from the cows, the bedding, the fod- 

 der, and the attendants. For this reason, the nature of the bedding 

 and the time of feeding play an important part in the production of 

 sanitary milk. Straw bedding contains a greater number of bacteria 

 than do peat or shavings. 



The handling of fodder during the time of milking disseminates 

 large quantities of dust, a considerable portion of which finds its way 

 into the milk, and, for this reason, it is customary to recommend that 

 feeding time and milking time should be separated so as to avoid as 

 much as possible this source of contamination. The nature of the bac- 

 teria derived from fodder is similar to that of the bacteria derived 

 from bedding. 



The following table, compiled from the experiments of Backhaus of 

 Konigsberg, will show the possible sources of contamination at a 

 glance : 



TABLE I 



Elements of Contaniinttion. 



1. Infection, — — 



2. Bodily cleanliness, i— 



3. Litter, , 



4. Influence of the litter on the number of bac 



teria in ntilk. 



5. Food (dust of, in the byre), 



6. Milking, „ — 



7. Vessels, 



8. Cleaning of vessels, 



Sources of Contanil- 

 nation. 



Fresh mili, 



Afttr passage through 



six vessels, 



Millt from c]»an cow. 

 Milk from dirty cow. 



Peat, _- „ 



Good straw 



Bad straw, 



With peat litter, 



With straw litter, 



Oil cake, 



Bran, 



Milked dry 



J^^ilked wet, 



First milk, 



Last milk, 



Washed udder, 



Unwashed udder, 



Enamelled vessel, 



Tin vessel 



Wooden vessel, 



Slierilized pail, 



Simply rinsed, 



Bacteria. 



6,660 per c. c. 



97,600 



20,600 



170,000 



2,000,800 



7,500,000 



10,000,000 



3,500 



7,330 



457,500 



1,361,000 



5,600 



9,000 



10,40# 



Sterile. 



2,200 



3,800 



1,105 



1,600 



279.000 



1,300 



28,600 



per c. c. 

 per c. c. 

 per c. c. 

 per gm. 

 per gm. 

 per gns. 

 per c. c. 

 per e. c. 

 per gm. 

 per gm. 

 per e. e. 

 per c. c. 

 per c. c. 



per c. 

 per c. 

 per c. 

 psr c. 

 per c. 

 per c 

 per c. 



15—6—1911 



