A higher feed intake in the weaning section is conditioned by the water consumption. It is very important that in the first 2-3 weeks after weaning all the piglets are activated from time to time to drink fresh water - ('milk soup' is helping also to prevent piglet’s dehydration - but is not sufficient). See more in this video
Restrictive feeding may reduce the incidence of post-weaning diarrhoea during the first two weeks. However, to avoid limiting the supply of nourishment and energy to the intestines, restrictive feeding is not recommended in the first three to four days post-weaning.
Where diarrhoea problems occur, one way to alleviate them is to reduce the protein in feed by between 5% and 10%. It should be noted, though, that this will reduce productivity.
A high-calcium feed also increases the risk of diarrhoea and may be reduced by 5% to 7%. This makes it necessary to reach a balance between a reduced diarrhoea risk and maximum bone mineralisation. Smaller pigs diets in particular are lower in calcium.
Gastrointestinal tract are still under development when piglets are weaned. And it is crucial to keep feed intake (constant nutrient supply) and to avoid that the intestine becomes empty. This is to ensure proper development and height of gastrointestinal villi and then good absorption of nutrients.