SQP – CPD Programme
As part of AMTRA`s online CPD Programme for livestock SQPs, each month AMTRA will send you the Parasite Forecast which
will highlight the parasitic challenge facing livestock in your area for that month. At the end of the Parasite Forecast you will
find a series of multiple choice questions (quiz button) based on its contents. Answer the quiz online and you will be emailed
a certificate with your score. This will form part of your SQP CPD requirement. The Parasite Forecast has been developed by
NADIS (National Animal Disease Information Service) and is written by leading veterinary parasitologists and based on
detailed data from the Met Office. Merial Animal Health is committed to the provision of up-to-date independent knowledge
for Animal Health Advisors to enable timely and best practice advice to be given to livestock farmers. As such Merial Animal
Health is proud to sponsor NADIS and the Parasite Forecast.
NADIS Parasite Forecast – May 2017
Use of meteorological data to predict the prevalence of parasitic diseases
Regional Weather
(based on Met Office figures)
Temperature: March 2017
(as °C Above/Below Regional Average 1961-1990)
Temperature: January - March 2017
(as °C Above/Below Regional Average 1961-1990)
Rainfall: March 2017
(as % Above/Below Regional Average 1961-1990)
REGIONS
0 N W Scotland
1 E Scotland
2 N E England
3 E Anglia
4 The Midlands
5 S England
6 S W Scotland
7 N W England
& N Wales
8 S W England
& S Wales
9 N Ireland
Rainfall: January – March 2017
(as % Above/Below Regional Average 1961-1990)
The weather in March was mild with mean maximum temperatures 1.5 - 2.5°C above average across most of the country. Rainfall was below
average in the south-east and in parts of Scotland, but above average in Wales, north-west England and the Borders.
May Parasite Forecast/Update
The most recent version of this monthly parasite forecast may be accessed at www.nadis.org.uk.
SHEEP
Parasitic Gastroenteritis (PGE)
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Ewes grazing heavily infected pastures and treated with a
short-acting wormer at turnout, may require further
Supported by
worming treatments to limit pasture contamination during
the ‘peri-parturient rise” (PPR).
o Aim to leave a proportion (~10%) of the ewes
untreated by targeting treatments based either
on body condition or faecal egg counts (FEC).
Improving sheep and cattle health
o
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Ewes treated with a persistent anthelmintic
before turnout should require no further
treatment.
Lambs on contaminated pastures should be wormed from
6 weeks of age onwards, based on the Nematodirus risk
(see below), and for other worm species by monitoring
clinically, or by FEC.
Ewes on safe grazing shouldn’t need worming again.
Lambs on safe grazing shouldn’t need worming until after
they are weaned.
Ideally wean the lambs onto aftermaths, with decisions to
treat based on either clinical signs, or on faecal egg
counts.
Nematodirosis
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Severe outbreaks of disease due to the parasite,
Nematodirus battus may occur in May depending on
several factors:
o A cold late spring followed by a sudden rise in
temperature can trigger a synchronised, mass
hatch of infective larvae on heavily
contaminated pastures grazed by last year’s
lamb crop.
o If this coincides with the presence of
susceptible, 6-12 week-old lambs then
scouring, severe production losses, and
sudden deaths may follow.
March was mild with mean temperatures 1.5 - 2.5°C
above average across most of the UK continuing the trend
for above average temperatures over the last few months.
Consequently, the NADIS and SCOPS Nematodirus
forecasts by mid-April, were predicting an early spring
hatch spreading northwards with moderate to high risks
for early lambing flocks with susceptible grazing lambs.
Continue to monitor the NADIS (www.nadis.org.uk ) and
SCOPS (www.scops.org.uk) websites for updates on the
situation as temperatures rise in the north.
White drench (1-BZ) wormers are still generally
recommended to control Nematodirus and in severe
outbreaks it is important to treat all lambs in the group
immediately.
The FEC of several lambs should be checked 10 days
later for the presence of other worm species, which if
present, would require treatment with a wormer from
another group due to 1-BZ resistance.
Coccidiosis
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Later born lambs, particularly twins grazing contaminated
pastures, may be affected by coccidiosis around 4-8
weeks of age.
Adverse weather conditions, poor colostrum supply,
overcrowding, wet muddy paddocks previously grazed by
sheep, and/or extended housing periods all predispose.
Avoid heavily contaminated pastures, particularly those
grazed by earlier born lambs and those grazed by last
year lamb crops.
Batch rear lambs of similar ages and consider creep feed
especially during periods of inclement weather.
Disease prevention can also include strategic dosing
lambs on contaminated pastures with diclazuril or
toltrazuril at around 3-4 weeks of age, or providing
medicated creep feed containing decoquinate for 28 days.
Lambs on safe grazing should not require anthelmintic
treatment until after weaning. Treatments can be further
avoided by moving weaned lambs to aftermaths.
Scour in lambs grazing contaminated pastures may be
caused by nematodirosis or coccidiosis. For advice on
diagnosis and correct treatment consult your veterinary
surgeon.
Liver fluke
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A high-risk of liver fluke disease was predicted for
Scotland, NW England, and North Wales for last
autumn/winter.
Sheep on farms with a known fluke problem in these
regions should be dosed in the spring with a flukicide
active against adult flukes to limit pasture
contamination with fluke eggs.
Avoid the use of triclabendazole as it may hasten the
selection for resistant strains of liver fluke.
High rainfall in May and June favours proliferation and
infection of the snail intermediate hosts, which may
lead to increased risk of severe fluke infections later
in the season.
NADIS will be producing more localised fluke
forecasts later this year – watch out for further details.
Blowfly strike
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Fly strike caused by the larval stages (maggots) of the
blowfly Lucilia sericata (greenbottles) affects around 80%
of UK sheep flocks each year.
The severity of fly strike is highly variable depending on
several factors including the weather.
Failure to treat promptly is a welfare issue and can lead to
reduced performance, secondary infections and death.
Even very small fly strike lesions cause disrupted grazing
and rapid weight loss.
Female flies are attracted by the odour of decomposing
matter such as wounds, soiled fleece or dead animals.
Footrot lesions, dermatophilosis (lumpy wool), and urine
scalding around the prepuce also attract egg-laying adult
flies.
Preventing diarrhoea caused by parasitic worms will
greatly reduce the risk of blowfly strike on the breech.
The blowfly season usually extends from May to
September but with changing climate the season can be
from March through to December in some regions.
Parasite control plans should include blowfly protection
during the fly-risk period and fit with the need to control
other parasites.
Topical preparations containing the insect growth
regulators (IGRs) cyromazine and dicyclanil, which
prevent blowfly strike, should be applied before the
identified risk period.
o Cyromazine provides protection against
blowfly strike for up to 10 weeks.
o Products containing dicyclanil afford 8-19
weeks’ protection against blowfly strike
depending on product choice.
•
Repeat treatments may be required, depending on
the product used, and season length, necessitating
careful planning when treating lambs due to the long
meat withdrawal periods.
•
Pour-on preparations containing cypermethrin provide
protection against fly strike for up to 6 to 8 weeks;
alpha-cypermethrin products provide protection for 810 weeks.
•
These products can also be used for the treatment of
active maggot infestations.
•
Deltamethrin spot-on products are used for treatment
of blowfly strike only and provide no protection.
•
Diazinon dips treat active maggot infestations and
provide good protection against blowfly strike for up to
6 weeks.
Blowfly strike attracted by neglected footrot lesion.
Cattle PGE
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Weaned dairy or beef calves in their first grazing season
that are turned out onto “safe” pasture (fields grazed by
sheep the previous year or previously arable) should not
require worming.
In contrast, calves turned out onto “high-risk” pasture
(fields grazed by calves the previous year) should be
wormed at, or around, turnout to limit acquired worm
burdens and reduce further pasture contamination.
o With these calves, the aim is to minimise pasture
contamination through further strategic treatments
where required, up to mid-July by which time any
over-wintering larvae should have declined to
insignificant levels.
o Strategic treatments include administration of
either a pulse or continuous release bolus at
turnout or administration of pour-on, or injectable,
macrocyclic lactones (MLs) at defined intervals, as
recommended by the manufacturers.
With both strategies calves should remain set-stocked, or
moved to safe pastures (aftermaths) when these become
available.
Flies
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There are many common species of flies which feed on
grazing cattle.
Biting flies, which include stable flies (Stomoxys), horn
flies (Haematobia), head flies (Hydrotaea), horse flies
(tabanids), midges (Culicoides) and blackflies (Simulium)
feed by puncturing the skin directly and may act as
vectors of several bacterial and viral diseases.
Nuisance flies, such as face flies and sweat flies,
scavenge the surface of the skin, wounds, or body orifices
feeding on sweat, skin secretions, tears, or saliva.
Face flies are often the most numerous nuisance flies
causing serious annoyance to grazing cattle and are
linked to the transmission of diseases such as summer
mastitis, New Forest Disease (“pinkeye”), and possibly
BVD virus.
Midges transmit bluetongue virus (BTV) and
Schmallenberg virus (SBV)
Insecticide impregnated ear tags should be applied at the
start of the grazing season to the whole herd to provide
season long protection.
Flystrike problem waiting to happen – this lamb must be
“dagged” immediately and a suitable preparation applied
topically to prevent myiasis. A review of PGE control
measures on the farm should be undertaken with the
farmer’s veterinary surgeon.
Don’t forget to try the interactive quiz
Local farm conditions may vary so consult your veterinary surgeon. Parasite control
should be part of your veterinary health plan.
To watch a webinar (video) based on this article and take an electronic quiz worth 3 CPD points,
click WEBINAR.
Copyright © NADIS 2017
Supporting Knowledge Transfer
NADIS seeks to ensure that the information contained within this document is accurate at the time of printing.
However, subject to the operation of law NADIS accepts no liability for loss, damage or injury howsoever
caused or suffered directly or indirectly in relation to information and opinions contained in or omitted from this
document.
To see the full range of NADIS livestock health bulletins please visit www.nadis.org.uk