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SUMMER 2014 ISSUE
LIVESTOCK MATTERS
24
B IOSECUR I TY FEATURE
Maternally Derived
Antibody (MDA)
Certain vaccinations are administered to
pregnant ewes in order to pass on protective
immunity to their lambs, helping to guard
against a range of neonatal lamb diseases,
chiefly the clostridial infections. For these vaccines
to be successful the lambs must receive adequate
colostrum as soon as possible after birth. The
quantity and quality of a ewe’s colostrum is
dependent on adequate nutrition, particularly
during the third trimester of pregnancy.
Antibodies are passed to the lamb in huge
quantities in the colostrum and absorbed
through the gut into the circulation. This is how
newborn lambs are able to protect themselves
against disease.
Lambs will have greatest absorption during
the first six hours of life. The ability to absorb
antibodies then declines rapidly, with essentially
no transfer after the first 24 hours of life.
With multiple births the proportion of colostrum
and hence antibody available to each lamb
is reduced.
Diseases for which there
is a currently licensed
vaccine for use in sheep
in the UK
Administer the correct
vaccination course
Vaccination protocols will often require
that the product is administered at a
specific time of the production cycle.
Where a primary course requires two
doses to be administered at a particular
time interval, it is important to follow the
protocol carefully. Omitting to give the
second dose prevents a satisfactory
immune response being stimulated
and can lead to total failure of the
vaccination regime.
Avoid multiple vaccines
Never mix vaccinations in the same
syringe and always inject different
products at different sites on opposite
sides of the neck if possible. Only use
two vaccines at the same time if they are
specifically licensed to be given together.
Store vaccines correctly
Vaccines must be stored at fridge
temperatures at all times. Coolboxes are
a simple and effective way of keeping
vaccines at the right temperature in transit
or while waiting to be administered.
Only vaccinate healthy
animals
Vaccination of sick sheep will lead to
failure of the vaccination and can in some
cases cause significant adverse reactions.
Use appropriate handling
facilities
Handling systems need not be complicated.
The aim should be to restrain sheep firmly
to facilitate injection.
Inject into the correct site
Vaccines are generally administered in the
neck. Check the data sheet to find out if
the vaccine you are using should be
administered subcutaneously (under the
skin) or intramuscularly.
Use suitable vaccination
equipment
Needle hygiene is critical to preventing
injection site abscesses. Always use sharp,
sterile needles, and where an automatic
vaccinator is used, the needle should be
changed every 20 doses. If vaccinating
small numbers of sheep with a single dose
needle, do not re-insert the needle into the
vial of vaccine. Leave one needle in the
vial of vaccine for drawing up and use
others for injecting the sheep.
Multi-dose, automatic vaccinators can be
used very effectively to administer vaccines
efficiently and cleanly. It is important to
clean such equipment and dry it thoroughly
after use. Any fluid, detergent or residual
vaccine material could interfere with
subsequent vaccines.
We strongly recommend farmers using
multiple dose guns to consider the
Sterimatic system which cleans the needle
between each injection to minimise the risk
of injection abscesses.
Figures 2 and 3 show the Stericap. This
contains a foam insert soaked in a liquid
disinfectant. The needle passes back and
forth through the disinfectant each time it
is pressed through the animals’ skin. This
has been proven to be very effective at
preventing the transmission of both bacterial
and viral contaminants from sheep to sheep
during vaccination.
How do you ensure effective vaccination?
Vaccines play a vital part in optimising flock
health. In order to maximise their potential,
it is important for both vets and farmers
to ‘read the small print’ and pay attention
to specific storage and administration
instructions. A yearly flock health plan or
equivalent can be an excellent point of
contact between vets and farmers to discuss
the different vaccination protocols suitable
for each individual flock.
Conclusion
Disease agents covered
l
Blue Tongue Virus
l
Clostridial disease and Pasteurella
l
Chlamydial (Enzootic) Abortion
l
Louping Ill
l
Orf
l
Paratuberculosis (Johne's Disease)
l
Pasteurella
l
Schmallenberg Virus
l
Toxoplasmosis
l
Clostridial disease (not all vaccines
cover the same species of clostridia)
When vaccinating use appropriate handling
facilities to restrain sheep to facilitate injection
Figure 2: Stericap
Figure 3: Needle is cleaned by Stericap
Figure 1: Sterimatic multi-dose syringe