Maternally Derived Antibody (MDA)

Nature has equipped the bitch and queen with the ability to pass on some of its own immunity (in the form of antibodies) before and shortly after giving birth (this is referred to as Maternally Derived Antibody - MDA). Whilst some of this immunity passes across the placenta to the young in the later stages of pregnancy, most is passed on in the first milk (known as colostrum).

It is important that puppies and kittens suck early because antibody levels (MDA) in the colostrum are at their highest at the time of birth. Furthermore, the newly born puppy or kitten is only able to make best use of MDA during the first day or two of life. After this time, the ability to absorb antibodies directly from the gut into the blood stream is lost.

So if all has gone well, the young puppy or kitten will have received adequate "natural" maternal immunity from the mother to enable it to resist disease for a period of some weeks. However, the extent of the protection depends on the immune status of the mother (she cannot pass on what she does not have) and how quickly and how well the young have sucked.

In turn, the immune status of the mother is nowadays highly dependent on whether she has been properly vaccinated up to date - the better protected the mother, the wore opportunity she has of passing good levels of immunity to her offspring.