This experiment was conducted at the experimental farm of AgroParisTech, Thiverval-Grignon, France. Forty, primiparous
and multiparous, Holstein cows, calving between November 2008 and July 2009, were used in the experiment. On the day
of drying-off cows were allocated to one of two dietary treatments: maize silage based control diet (C, n = 20) or control
diet plus 1 g -carotene/cow/day