Cross-feeding of infants generally relates to bottle-feeding in today’s world, but there have been periods in history when a range of cross-feeding approaches were attempted, including such approaches as the smearing of animal blood on a mother’s breasts with the intention to raise a child as a warrior. There have also been periods in history when the colostral feed was seen as a contamination of the mother’s milk and was therefore withheld from the infant.  Human knowledge is always bounded by custom and belief.

By comparison we may think that today’s formula feed is less harmful, because it has been scientifically formulated and prepared in relatively sterile conditions. However, the truth is rather different. Because of the complexity and wide range of ingredients, the total allergenicity of formula milk is high, but, because it is physically a milk, it tends to be absorbed and dealt with as if it were, physically, human milk.  It thus becomes distributed around the neonate body as if it were human milk, and so, at the same time, delivers its allergenic ingredients across all body systems – the worst possible outcome!

For newborn infants, dealing with the burden of foreign (non-maternal) foodstuffs results in consequences that we know as ‘western diseases’.  For formula milk components of bovine origin, any immune reaction to them is generally reinforced by the further consumption of foods of bovine origin, in later childhood and in adult life.  The immune system is thereby challenged to produce antibodies to bovine antigens at every meal and tea break and the body becomes awash with antigen-antibody complexes, these in turn begin to threaten the health of the individual; a typical result might be asthma and / or the propensity for anaphylactic shock.

Whether a formula feed is based on dairy or soya milk, or some other sources, a similar pattern of consequences ensues and the individual recipient’s life becomes burdened by the atopic disease symptoms that appear.  Some relief may be gained by restricting the diet to one free of foods of bovine origin, but this is difficult to achieve.

What we have done to our own population, by bottle-feeding of infants, is reflected in our pets, especially dogs, which now suffer a wide gamut of atopic disorders because dog breeders keep unusually large litters alive, partly through bottle-feeding.  The problems posed by cross-feeding of neonates are better understood by vets than by medics.  The final outcomes are generally, poorly understood.