Feed International - August 2017 - 14
14 ❙ FeedInternational
Balanced nutrition greatly
affects immune function,
performance in transition cows
The immune system is a biological defense system comprised of
different structures, cell types
and processes that act to protect
the host animal from pathogens. Pathogens include microorganisms, viruses and parasites.
As such, the immune cells must
be able to differentiate between
healthy host tissues and cells and
those of a pathogen or tumor.
The immune system is a complex, tiered arrangement that facilitates detection. The initial line
of defense is usually physical in
the form of a barrier, such as the
epithelium. Cuts or abrasions to
the skin can allow entry of pathogens into the body that subsequently stimulate the next step in
the defense process - the innate
immune response. This response
causes inflammation and is immediate but non-specific, meaning
that it reacts in the same way, no
matter what the pathogen is.
A second aspect of the immune system is the adaptive or
acquired immune response. This
is more complex than the innate
system as it involves recognition
of specific, individual pathogens.
Antibodies are produced as part
of this response and activation of
the adaptive immune response
forms the basis of vaccination.
This system also poses "memory" whereby memory cells from a
previous infection remain in circulation and if the same pathogen
is encountered for a second time,
the response is more rapid and of
The failure of any stage of defense leaves the animal at greater
www.WATTAgNet.com ❙ August/September 2017
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BY HELEN WARREN