Animal plasma is a unique ingredient in that it invariably increases animal
performance, the more under less healthy conditions. Previous research has
clearly demonstrated it is the heavy molecular weight fraction of animal plasma,
which contains the immunoglobulins, that is largely responsible for improved
gastrointestinal health that manifests into enhanced growth, evidenced by higher
feed intakes post-weaning.
Yet, animal plasma has a strong negative
feature. It is very expensive. Especially following the reintroduction of
(porcine only) plasma in the European Union, this ingredient accounts for over
one third of overall feed cost, even when it is included in a moderate 2-3% rate
in post-weaning feeds. Animal plasma has always been expensive, but today it has
become almost impossible to use it.
So, how to replace it? The only
direct solution is to find other sources of immunoglobulins such as those from
bovine colostrum and hyper-immunised eggs. Unfortunately, these products are
either too expensive themselves, or otherwise too specific against certain
strains of pathogens.
In my opinion, the best way to reduce
dependence on animal plasma is by improving overall animal health, as it has
been shown plasma exerts its highest effect on less than optimal health
conditions. Improving diet quality and complexity also reduces the need for
animal plasma. For example, increasing lactose by 5% can reduce dietary animal
plasma by 1%, at least in most cases! Finally, it should be kept in mind that
animal plasma should be used only up to the level that induces a substantial
increase in feed intake. For most high quality diets this level is around 3%,
but for lesser feeds this level may be increased up to 5%!
One final
aspect in selecting animal plasma sources; our research has clearly demonstrated
that the level of crude protein is a poor index for predicting animal
performance. In contrast, the level of immunoglobulins, and even more
specifically IgG, is the best index in selecting sources of animal plasma. On
average, a good source of plasma should be able to guarantee a level of around
15% IgG.