Calves and piglets do not receive immunoglobulins via the womb before they are born. Immediately after birth, their immunity is based solely on the colostrum they receive in the first few hours of life. This means that newborns are particularly sensitive to pathogens.
In calf-rearing, cryptosporidiae are becoming an increasing problem along with the known pathogens that cause diarrhoea. Streptococci are among the most common pathogens on pig farms.
Stress is also known to affect the immune system. Animals are exposed to stress in particular immediately after birth, during the rearing period, when arriving in a new pen or when their feed is changed. At these times they also often suffer from a lack of vital nutrients and active ingredients.
It makes sense to provide a feed that boosts immunity and robustness in order to ensure safe rearing even in the context of a higher level of infection and when stress factors are present.