[Organizing mastitis control (author's transl)]

In view of the considerable losses caused by clinical, though particularly subclinical, mastitis, organized mastitis control is justified. Cell counts of herd milk samples are the most effective method so far available in detecting herds in which mastitis is a problem. Cell counts are primarily made to determine the quality of the milk delivered; secondly, cell counts are used in mastitis control. Using the same cell count in determining the quality and in detecting herds affected with mastitis is a difficult matter. Herds in which mastitis is a problem, are systematically detected in a limited number of provinces in the Netherlands. In mastitis control on a farm, particular attention is paid to: (1) hygiene on the farm (2) the house climate (3) special arrangements for maintenance of the milking plant (4) the procedure adopted in milking (5) teat dipping (6) dry cow therapy (7) culling chronically infected cattle. Because of mastitis in the cows, there may be an increase in bacterial counts due to streptococci causing mastitis in addition to cell counts in herd samples. These streptococci are perceptible in the form of small punctate colonies, so-called pin-points, in bacterial counts. Bacteria other than streptococci causing mastitis may also produce these pin-points. In recent years, the cell counts of herd milk samples showed a marked decrease in the southern Netherlands. This decrease was due in part to the large number of improvements in the milking apparatus. Moreover, intensive education by lectures, excursions and counselling of factories has also stimulated this favourable development. However, these effects are hard to measure. The continued reduction of the cell count in herd samples imparts confidence in the results of this mastitis control.