for Responsible Cow Health Planning
by Robert S. Seddon ADRN
we can talk about vaccinations and if or if
not to employ them in your breeding program,
we first need to understand how the immune system
works and what types of immunity are and how
we get them. This is the first in a series of
articles that I hope will cover the entire topic
reasonably, so I call it “Immunity 101”.
I am sure that we have all heard the good old
“We have a closed herd, and don’t
do anything at all” approach to this topic,
and I really need to wonder about it. If you
NEVER buy a cow or calf, and NEVER sell a calf
from your herd, this holds somewhat true, but
how many of us can really say this? Even if
you never vaccinate, your bovines will gain
a level of immunity to the normal bacteria that
exist in their environment as their own immune
system will generate antibodies as they are
exposed to them.
What about a deer or two running through your
field and exposing them to Hoof and Mouth Disease
or another new strain of pathogenic organism?
What about a fly landing on the eye orbit of
a cow with pink eye, and then traveling up to
three or more miles to land on your cows eye?
(Flies can travel up to three miles on their
own, but what if they are transported in a stock
trailer or truck?) These are all scenarios that
we need to evaluate and make decisions about
as we formulate a responsible health care plan
for our herds. It only takes one outbreak of
something to quarantine and destroy what you
have spent a lot of your energy and life to
The immune system is a part of the animals lymphatic
system that deals with the production of Lymphocytes,
Monocytes and Phagocytes (Macrophages) that
protect the animal from foreign bacteria and
viruses by producing antibodies, mounting a
cellular level attack on the foreign bodies
and by Phagocytosis (Engulfing and eating the
foreign cell or virus).
Natural Immunity is a genetic predisposition
present in the body at birth, which is not dependant
on previous exposure to a pathogenic organism
to produce antibodies or to mount a response
from the immune system. Dexter cattle as a breed
seem to be blessed with a strong natural immunity
that will assist in warding off many of the
usual calfhood problems that are evidenced in
many other production breeds.
Acquired Immunity comes in two types, active
and passive, and is the main part of what this
article will deal with.
Acquired Active Immunity is gained through exposure
to the disease and the resultant production
of antibodies against it, or through vaccination
with a modified or half dead pathogen or toxin
that stimulates the lymphocytes to produce antibodies
against it without actually getting the disease.
Obviously, the second way to get active immunity
Acquired passive immunity is what one gets by
injecting antibodies produced in another animal
into the diseased animal, This type of immunity
is deployed when immediate protection is needed
such as immunoglobulins given to a very sick
child, or antitoxins to treat a snake bite.
Acquired passive immunity is also applied by
passage of the immune bodies through the mother’s
placenta before birth and through ingestion
of colostrum in the first 12 hours after birth.
(After the first 12 hour window, the semi permeable
membranes in the calf’s intestines and
GI tract change to a state where these antibodies
can no longer be absorbed into the calf.) This
passive immunity is powerful, but short lived,
as the calf has no mechanism to produce more
of the antibodies as they wear out over time
(about 6 to 8 months on the passive immunity
from the colostrum) and this is where the acquired
active immunity from vaccination should be applied,
as the calf will make the antibodies itself
and gain the mechanism to continue to produce
With this information in mind, one next needs
to construct a biosafety profile for their own
farm. Each farm has its own set of circumstances
and farm practices to deal with, and I will
only cover a few here.
Low Level Biosafety: No animals are brought
in as replacements or for breeding, and the
nearest bovine facility is over 25 miles away.
No other farms equipment will be used or brought
on to the premises. Few or no visitors.
Mid Low Biosafety Level: Only a few animals
are brought into the farm over a year, but have
full vaccination and health papers before entering.
New animals are quarantined for 4 weeks before
exposing them to the herd, and are evaluated
by a professional vetinary before release. An
occasional stock trailer is brought in to deliver
or take animals out of the farm.
Mid Level Biosafety: 5 or more cows/steers/bulls
are transported onto the farm over a year, all
incoming animals are fully vaccinated with health
papers from a vetinary, no quarantine is used
for the incoming animals. Other farms equipment
is in use, and there are other bovine facilities
within 5-10 miles.
High Level Biosafety: 10 or more animals change
hands per year on the farm, vaccination records
of the incoming are incomplete or non existent,
stock auction activity is common, many visitors
and trailers/equipment are coming and going,
heavily populated bovine area.
My farm is in the Mid Low Biosafety category,
and due to that fact I need to form a vaccination
plan for my animals. I have said nothing about
if you sell a calf or two, as from what I have
seen many run on the “Buyer Beware”
principle. Even if there are no diseases on
your farm, that calf is going out into the cold
dark night with no pajamas on if he is not vaccinated,
as he might have natural active immunity against
what is on YOUR farm, but what about where he
is going to? Many buyers are new to cattle and
not aware of these considerations when they
first buy a calf, and I have heard more than
a few bad tales about the outcomes. All of our
calves are sold with a full set of vaccinations
and a full set of boosters after a month, full
health papers from our vetinary, and transfer
to the new owner paid for in the sale price.
The next installment on this series will deal
with taking the Biosafety Levels and designing
a vaccination plan that suits your own farm
Please remember that this is an over simplified
presentation of this topic, and I would appreciate
any comments or suggestions to try to make this
easier to understand and educational.
Olde Towne Farm