From 1974/1975 to 1976/1977, a 2 year dairy herd health and management program was carried out in the Netherlands, including 30 program and 31 control farms. The year 1974/1975 was used as a base year, before the program started. After 2 years of program application, the gross margin per cow per year (calculated as total returns minus feed costs) increased Dfl. 176 more on the program farms than on the control farms. This increase equalled about 8% of the initial income level. To gain insight into the level of income after the experiment had finished, data from both groups of farms were gathered for the years 1980/1981 and 1985/1986. Data became available from 15 program and 20 control farms, and were analyzed to see whether the initial effect on income had increased, decreased or stayed the same. In the first few years after the program had finished (1976/1977-1980/1981 ), the gross margin per cow increased Dfl. 322 more on the control farms than on the program farms as a result of higher milk production and lower feed costs. In the period 1980/1981-1985/1986, the increase in income for both groups was almost the same (slightly more than Dfl. 1000 per cow). Hence, the initial increase in income disappeared soon after the program had finished. It seems to be profitable, therefore, to apply herd health and management programs to farmers on a more than temporary basis.