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B IOSECUR I TY FEATURE
SUMMER 2014 ISSUE
LIVESTOCK MATTERS
22
On-farm
biosecurity
measures
In TB areas, or where badgers are present,
then there is the possibility of TB-infected
badgers coming into contact with cows at
grass. However, many other risks can
be minimised or prevented by taking
appropriate action.
Cattle can become infected with bTB
from other cattle in a number of ways; by
co-grazing, (for example on common land),
shared housing; at shows; returns from market;
and grazing/housing away from home
premises with direct (nose to nose) or indirect
(e.g. shared water) contact with other herds.
To reduce the opportunity for disease spread
from nose to nose contact whilst cattle are
at grass, inspect your field boundaries; a
separation from your neighbouring cattle fields
of at least three metres is recommended. Also
check your fencing; is it robust enough to
prevent cattle escaping into the next field and
mingling with another herd
?
Where fields are next to, or include woodland
or scrub inhabited by badgers or deer that
could harbour TB, consider whether these
areas could be put down to other crops or
grazed by non-bovines.
If there are populations of badgers present
on and around the farm, securing feed
stores should be the main priority, closely
followed by cattle housing and feed areas.
Although difficult it is always possible to
secure buildings. Badgers can access through
any gap greater than 10cm (the height of
most mobile phones), so checking entry points
(figs 1-3) is recommended.
Although passive fencing is best, to prevent
badgers accessing maize silage clamps and
feed stores, it may be necessary to use electric
fencing (three strands at 10cm, 15cm and
20cm from the ground).
Reducing contact at pasture is much more
difficult. Recent evidence shows that nose to
nose contact between badgers and cattle is
rare, so the main risk at pasture is probably
badger urine and faeces which are
concentrated around setts and latrines.
Fencing off these areas is well worth the effort,
but remember to do it in such a way that the
area can be cut back to prevent it reverting
to scrub, which would cause the latrines to
be moved further into your fields.
Any livestock transport vehicles, cattle crushes
or slurry and manure equipment that are
shared between farms or hired in, should be
thoroughly cleaned and disinfected before
introducing your stock to them.
Manure, slurry, and dirty water from another
farm are also potential sources of bTB (and
other) infection and should not be spread on
livestock pasture.
The use of foot dips by visitors and staff is
another overlooked safety precaution that can
be taken against disease spread.
Buying-in cattle
Whether you are on a farm which is in
the clear for TB and wanting to expand
your herd number, or looking to replace
stock lost in a recent TB shutdown, it is
still important to follow biosecurity
procedures when bringing new cattle
to the farm.
A pre-movement TB test carried out on
animals before they move to the farm
may identify any that have TB lesions
at that time. A recent clear whole herd
test is better evidence that the bought-in
animal is uninfected, however, TB is a
slow chronic disease, and it takes time
for infected animals to become
detectable. This means it is still possible
that they could be TB-infected, but not
react to the skin test. So don't rely just on
one pre-movement test. Instead, when the
animals arrive on your farm, quarantine
them for at least two months, and then
test again.
MARKABOND/shutterstock.com
Figure 1
Figure 2
Figure 3
The above security precautions
are relevant not only for
bTB
,
but also for infectious diseases
such as
BVD
and
leptospirosis
.