The objective is to investigate the interaction between feeding strategy and an extended lactation
in dairy cows with focus on metabolic adaptation (plasma metabolites and hormones), mammary
gland adaptation (proliferation and apoptosis of milk synthesizing cells), efficiency of production,
reproductive parameters (embryo quality, WP4), milk quality (WP6) and environmental
impact (methane, N and P excretion per kg milk produced, WP7). An individualized and weightadjusted
feeding strategy in early lactation will be compared to a traditional feeding strategy in an
intensive experiment including seventy dairy cows at an 18-month calving interval. Modelling the
consequences of extended lactation and the interaction between performance, energy balance and
reproduction will be an integrated part.

Expected outcome:
1) A new concept including an individualized dairy cow feeding strategy supporting extended lactation
(increased yield and lactation persistency, without changing the efficiency) and late breeding
of cows at dairy farms; 2) reduced metabolic load and stress of dairy cows with an extended
lactation; 3) reduced environmental load per kg milk produced with the new concept; 4) new
knowledge on the physiological mechanisms behind the new concept; 5) A PhD.