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S H E E P F E A T U R E
SPRING 2010 ISSUE
GOOD MANAGEMENT ON THE FARM
In order to reduce the coccidiosis challenge
on the farm and protect lamb growth
rates, an integrated approach is best:
combine good flock management with
good farm hygiene measures and when
necessary, consider the strategic use of
a coccidiocide.
Dosing with an oral coccidiocide is the
most reliable way of ensuring that every
animal receives a sufficient dosage of
medication for effective control of the
disease. Coccidiosis is a highly contagious
disease, so all the lambs in a flock will
need to be treated against it.
By contrast, in-feed coccidiostats are
convenient, but they do rely on each lamb
getting a sufficient amount of medication
every day for at least 28 days. Lambs may
not be on creep at the time of challenge
and, even if they are, a lamb that does
not eat well, even for a short period, will
lose full protection. Also, coccidiostats do
not kill existing coccidia but merely prevent
further reproduction of the parasite in the
small intestine.
In order to diagnose whether diarrhoea
and/or poor lamb performance is due
to coccidiosis, faecal samples can be
taken for assessment of coccidial oocysts.
There are two species of the single-celled
organism Eimeria that are pathogenic to
sheep. Speciation of the oocysts in the
faeces (undertaken at a laboratory) will
determine if these are present, and whether
an anti-coccidial treatment is needed. It
is important not to rely simply on high
coccidia counts as there are many types
of coccidia that are not harmful.
As well as medication, the following
practical measures should be taken to reduce
the disease challenge to young lambs:
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Ensure good hygiene in the lambing
shed, and use plenty of clean bedding.
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Food and water containers should be
raised off the ground to avoid the risk
of contamination from faeces.
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If stocking rates can be lowered, then
this will reduce disease pressure.
l
Minimise stress to the lambs as this
undoubtedly exacerbates the problem.
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Avoid turning young lambs into areas
where older lambs have been.
l
Be aware of the possibilities of
Nematodirus worm problems in the
early summer - this may also be
relevant to 6-12 week old lambs,
causing diarrhoea and possibly
associated deaths.
Forecasts are available to predict the
risk of Nematodirus and when high,
farmers are usually advised to give one
or two doses (ten days apart) of a white
drench to those lambs at risk.
Finally...
If you think that coccidiosis is a problem
on your farm then always invite your vet
to come and review the situation with
you, and advise on how best to remedy
it. Dosing at the wrong time, or against
a disease which is not present, is just
a waste of time and money!
LIVESTOCK MATTERS
18
One memorable case was a farm that kept
lambs inside, in clean and well bedded
buildings, for a month before turning them
out into paddocks.
The stocking density outside was high and the
fields must have been highly contaminated
with overwintered oocysts. In the groups of
lambs that were released untreated, scouring
began a fortnight after turnout and some died
within two days of the start of the scouring -
with one group reaching a 10% mortality rate.
Scouring and deaths were only prevented
in the groups that were treated with an
anticoccidial, in anticipation of the problem,
in this case, just over a week after turnout.
Even in the absence of diarrhoea, sub-clinical
levels of coccidiosis will still compromise lamb
growth rates, and if left untreated can develop
into clinical disease.
Signs of coccidial disease in lambs include:
abdominal pain (lambs are hunched up),
straining as they pass faeces, dehydration
(lambs drink a lot at the troughs), inappetence,
reduced weight gain and general unthriftiness.
Coccidial infection, and the consequent
gut damage, also means the lamb is more
susceptible to secondary bacterial infections.
We would like to thank Bayer Animal Health, manufacturers of Baycox
Sheep for kindly supplying this image and for their support with this article.