The objectives of this thesis were: 1) to evaluate the variability in the modulation of prepartum dry matter intake (DMI) and its associations with transition metabolism, health, and performance; and 2) to assess the associations of rumination time prior to calving with the metabolism, health, and performance of dairy cows. Data on rumination and physical activities and blood metabolites improved the performance of linear models explaining the modulation of prepartum DMI. Cows with a large decline in prepartum DMI were fatter and heavier before calving, had impaired metabolism, but yielded more milk during the first 14 weeks of lactation. Although cows with a low level of prepartum DMI had similar metabolic outcomes, they produced less milk in the subsequent lactation. Regarding objective 2, cows with reduced prepartum rumination time had a challenging transition metabolism, but only multiparous cows were associated with a higher incidence of clinical diseases and impaired performance.