In the period of December 1996 to December 1997 seven dairy farms have been
monitored in monthly intervals. Milk samples were taken from all animals w
ithin the first eight weeks p.p. (n = 15.605) and the acetone concentration
s were determined with the flow injection analysis technique (FIA). Within
the first two weeks p.p. are 59 per cent (n = 352) of animals with elevated
concentrations (> 0,250 mmol/l). 82,7 per cent (n = 291) of these animals
have values of subclinical ketosis. Within the first six weeks of lactation
97 per cent (n = 578) of all individuals exhibited augmented milk acetone
concentrations. Both high and fluctuating shares of animals with high milk
acetone concentrations have negative effects on the average milk production
within a herd. During the winter period low rates of sick animals were fou
nd, whereas in May and August a maximum frequency was detected. The applica
tion of milk acetone determination in the monitoring of cattle herds facili
tates a reliable and permanent control of the energy metabolism of dairy co
ws. Problems concerning the energy supply can be detected and the effect of
countermeasures can be monitored with low efforts.