IMPORTANCE TO MILK CONTROL 143 



The individual percentage would show the following figures. 

 Of the total number of cows there are annually diseased : 



ca. 1.52 per cent, with Chronic udder-streptomycosis. 



ca. 0.45 per cent, with Udder-pyobacillosis. 



ca. 0.35 per cent, with Udder-tuberculosis. 



ca. 0.08 per cent, with Udder-actinomycosis. 



ca. 2.40 per cent, of the total number of cows showing udder- 

 infections. 



Out of 200 cows one may expect five cases of chronic udder- 

 infection yearly, and of these three are usually streptomycosis and 

 the remaining two may be one of the three other chronic udder- 

 infections. Of these pyobacillosis is the most common and occurs 

 in ca. 1 case in 200 cows ; next comes tuberculosis, ca. 1 case in 

 300 cows, and finally actinomycosis, the least frequent, with ca. 1 

 case in 1200 cows computed on a yearly basis. Naturally the 

 figures are not so uniform. 



The first two figures are fairly constant but the last two are 

 not. 



The figures on tuberculosis were taken from our most heavily 

 infected tuberculous districts and are therefore not a fair average 

 for the presence of tuberculosis in the entire country. The figures 

 for the whole country are decidedly lower. In certain parts of 

 Sweden, as in the north, udder-tuberculosis is very rare. Naturally 

 it is not present at all in the districts which are free from reactions. 



The figures on actinomycosis taken from the journals of the 

 Veterinary High School of material from the different regions of 

 Sweden are perhaps a fair average for the occurrence of this dis- 

 ease in the country. Actinomycosis, however, is not uniformly dis- 

 tributed in the country. There are regions where udder actinomy- 

 cosis occurs with relative frequency and others where it is not 

 present at all. 



