New Sore; Agrii oi.tws.al Experiment Statu <1 



washing the stable is an important sanitary practice with a strong 

 influence upon the quality of the milk. 



In public health regulations and in dairy score cards, which have 

 been designed to assist in the production of sanitary milk, much 

 emphasis has been placed upon the materials and the details of 

 construction of the stable and upon the care with which the interior 

 has been kept free of dirt. As explained in the introduction, these 

 regulations were formulated on the basis of very general information 

 and in the absence of exact data covering these points. The results 

 from the above careful measurements suggest that the importance 

 of barn construction has been considerably overestimated and that 

 within rather wide limits the condition of the stable exerts no measure- 

 able influence upon the germ content of the milk produced within it. 



EFFECT OF CLIPPING COWS. 



Clipping horses to facilitate cleaning is a practice of long 

 standing. Certified milk producers cornmonly clip the cow's udder, 

 the flank up to the hip joint and the long hairs on the tail above 

 the switch as well as shorten the switch if it tends to get into 

 the manure. In- the absence of any previous attempts at measuring 

 the influence of this practice the following experiments w r ere con- 

 ducted. 



These tests illustrate the difficulties which are inherent in experi- 

 mentation of this type. The individuality of the cow influences the 

 results so markedly that comparisons of simultaneous results obtained 

 from different cows have little value. On the other hand results 

 obtained from the same cow on different daj^s may be influenced by 

 changes in surroundings which it is difficult to control. In many 

 experiments these changes in the surroundings may be equalized by 

 using the cow on alternate sides of the experiment on succeeding 

 days and by using an equal number of cows on opposite sides of 

 the comparison on any given day. However, in such a test as this 

 where it is impossible to return a clipped cow to an undipped con- 

 dition for some months there is no escape from the necessity of 

 testing a cow for a period, clipping her and then completing the 

 comparison. 



In a preliminary experiment conducted in 1909 the germ content 

 of the milk from two cows was determined for six days. The udders 



