An epidemiological study of hyperketonaemia in Swedish dairy cows; Determinants and the relation to fertility

In a study based on 3078 Swedish dairy cows from 126 herds, milk acetone was measured at the first 3 monthly production tests after calving. The values were assessed together with data from the official milk recording system, artificial insemination records and the computerised recording system for veterinary treatments. Milk acetone concentrations above 0.40 mmol 1^?1 were considered to indicate hyperketonaemia. The prevalence of hyperketonaemia was 8.9, 4.7 and 1.1%, respectively, at the first 3 monthly production tests. A significant influence on milk acetone was found for herd mean production, breed, herd, lactation number, cow, week of lactation, season and the interaction between lactation number and week of lactation. The highest individual milk yield and highest individual acetone value were significantly positively correlated. Test-day milk yield and milk acetone on the same day were significantly negatively correlated. The recorded incidence of clinical ketosis and ovarian cysts increased with increasing highest milk acetone concentration. Significant correlations were found between the prevalence of hyperketonaemia and herd means of the intervals from calving to first and last service. No significant correlations were found between milk acetone and fertility traits when calculated on an individual cow basis.