Critical phases of the diseases
Days 1 to 10 of life: newborn piglets are exposed to a variety of pathogens which they can only be protected against by passive immunity. If the sow doesn’t produce enough colostral antibodies, or the piglets don’t get enough colostrum, the piglets are almost defenceless against E. coli and Clostridium perfringens type C.
Days 10 to 28 of life: For most of the vaccines a decline of passive immunity takes place after the first week of life. The piglets however stay susceptible to pathogens such as E. coli or Clostridium perfringens type C until their own immune system is well developed.
Around weaning the piglets are particularly susceptible to E. coli diseases because of feed and environmental changes, as well as the stress of weaning.