[Udder health on dairy farms. 2. Mastitis prevention programs].

Herd-specific mastitis control programmes are based on the continuous monitoring of primary parameters, of which the bulk milk somatic cell count and the distribution of pathogens responsible for clinical and subclinical mastitis are the most important ones. When a mastitis control programme is started, the herd situation should be analysed. Sampling milk from cows with clinical and subclinical mastitis is essential. During the last 5 years, a number of programmes related to udder health and milk quality have been started in the Netherlands. These programmes are: 1) 'Chain Quality Milk', 2) a herd-specific Mastitis Planner, 3) a sampling programme for subclinical mastitis, and 4) a combined analysis of milk recording data, and subclinical and clinical mastitis data. Using these four programmes, farmers, veterinary practitioners, and other advisors can design a herd-specific programme to improve udder health. Although there have been many studies on mastitis and important progress has been made, some important aspects have often not been studied. Suggestions for further research are made.