The effect of an immediate shift from milk to solid feed at weaning (30 d) was studied on intake, growth, caecal ecosystem and health of the young rabbit. Two groups of 11 litters were weaned at 30 d of age: PILA group, where the kits were fed exclusively with maternal milk until weaning, and then immediately fed with a pelleted feed; Control group where the kits were classically bred, with a progressive increase in feed intake before weaning from mother feeder. The adaptation of the young to the solid feed was quick, since their relative intake became similar to that of Control between 32 and 36 d (respectively 89.9 vs. 89.3 g/d/kg LW). From 30 to 49 d of age, the growth of PILA did not differ from Control (meanly 50.7 g/d). From 49 to 70 d, the intake of PILA group did not differ from Control, as well growth rate or feed conversion. The mortality (4/154) and the morbidity (3/154) were low and similar among the 2 groups. An exclusive milk intake till weaning strongly inhibited the pectinolytic and xylanasic bacterial activities at 30 d (respectively 7 and 4 times lower for PILA than for Control), but they were similar to Control at 37 and 44 d. The bacterial biodiversity in the caecum, estimated by Simpson index, did not change significantly between 30 and 44 d of age for the control group. In return, an exclusive milking reduced the caecal biodiversity at 30 d of age (PILA), but it increased rapidly and reached a level similar to control group at 37 and 44 d of age.