FLOCK HEALTH PLANS
Blood samples were taken from the aborted
ewes; four out of six ewes tested positive
for the parasite Toxoplasma gondii.
Bryony explains: ‘This parasite can cause
early embryonic loss, abortions, stillbirth,
mummified lambs and weak live lambs.
It is shed in cat faeces and the disease is
caused when the infective particles are
ingested during pregnancy.
‘Its control relies on avoiding contamination
of feed and increasing ewe immunity
through vaccination.’
Tim says: ‘Some of the fields are near
residential areas and there are a lot of cats
about. The vaccine looked quite expensive
at first, but Bryony explained that a single
injection will protect against toxoplasmosis
for a number of years, and so in
subsequent breeding seasons only
replacements will need to be treated.
‘Last year, around 10% of my ewes were
empty when we scanned them, and at
lambing we had a high number of singles
born - which we shouldn’t be getting with
mules. The cost of the blood tests was
equivalent to the price of two lambs...
so it should soon pay off.’
Tim’s breeding ewes are now protected
against Toxoplasma with a vaccine which is
given at least three weeks prior to tupping.
All the blood samples tested negative for
enzootic abortion (EAE). Bryony explains:
‘The majority of EAE outbreaks are caused
by buying in infected animals. Tim doesn’t
have a closed flock, so he ought to source
replacements from EAE-free accredited
flocks, or accept the fact he will need to
vaccinate against the disease if it enters
the flock.’
Blood was also screened for trace
elements; the levels of selenium, cobalt
and copper were normal, but iodine
was very low.
‘A lack of iodine has consequences for
fertility and peri-natal lamb health; it
increases the risk of still births and the
lambs born live can be weak and slow
to get up. There are various treatment
options; iodine drenches, water
supplementation and boluses. Tim opted
to use a bolus which would supply iodine,
selenium and cobalt and give ewes cover
for six months. It was given a few weeks
prior to tupping.’
Blood testing results
Bryony says: ‘Too many farmers are
worming according to a regimented plan,
or at the first sign of a dirty back-end. But
over-use of wormers has been a major
cause of wormer resistance; this is arguably
one of the biggest problems currently
facing the sheep industry.’
Worm egg count monitoring is a useful
tool to decide when worming needs to
be carried out.
Four weeks prior to faecal samples
being taken, Tim had wormed the lambs
with a white drench (benzimidazole).
However the egg count showed that
this had not been fully effective and so
Bryony advised that lambs be drenched
again to prevent growth rates being
compromised.
At the same time, samples were collected
and sent off for a free analysis of
coccidiosis. The coccidial oocyst count
was high, but these were found to be of
a non-pathogenic species and so no
treatment was necessary.
Faecal samples from ewes also tested
negative for presence of liver fluke eggs.
Wormer effectiveness
WINTER 2014/2015 ISSUE
LIVESTOCK MATTERS
10
Reviewing the plan
‘Ideally, flock health plans should be reviewed
at least annually, in order to keep progress on
track and alert to any new problems which
have arisen,’ says Bryony.
Due to Tim’s many other commitments, Bryony
hasn’t managed a formal meeting however
they have kept in contact over the course of
the year.
In 2014, Tim reported an increase in scanning
percentage to 195%, and fewer lamb losses.
However, lamb growth rates were still
disappointing. Tim explains: ‘I’d sold a few
singles at four months of age, but would have
liked to have sold more, the vast majority of
lambs were still on farm in October.’
Lambs had been treated with ivermectin
(clear) and benzimidazole (white) wormers
over the summer. Bryony came out to the
flock in September and took dung and blood
samples from some lambs which had been
wormed a few weeks previously with a high
dose of white drench.
‘The egg count was a bit higher than expected
considering the recent worming treatment. So
there is a high possibility that these worms are
resistant to benzimidazole drenches. Tim didn’t
need to worm them again, but further monitoring
of worm egg counts is recommended.’
The dung sample sent for coccidiosis testing
showed a higher presence of pathogenic
species this time. Bryony explains: ‘Although
there had been no overt signs of black tarry
scour, coccidial disease may have played a
role in poor lamb performance by checking
early growth. So I’ve recommended that Tim
routinely drenches lambs at 6-8 weeks of age
next spring.’
Taking the long view
‘Monitoring faecal egg counts is well worth
the effort,’ explains Bryony. ‘It may show
that wormer use can be reduced, and it
demonstrates the efficacy, or not, of a given
wormer, highlighting resistance issues. It also
gives an indication of the worm burden
on different pastures which can help with
decisions on pasture rotation.
‘The most profitable flocks are those that
rear the highest number of lambs as efficiently
as possible on their farm. But many flocks
are not realising their potential. It is well
worth discussing problems with a vet, so
that investigations can be made into the
possible causes and how best to rectify them.
Drawing up a flock health plan is a good
starting point.’
Tim adds: ‘I always think it’s best to take
the long view and look at tomorrow not just
today. Thanks to Bryony, I’m not going to be
repeating the problems I’ve had, because
we’ve found the causes and done something
about it.
In the future,
I’m expecting to
have faster-growing lambs and
be able to cut my medicine costs
right back!’
