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.

Improving sheep and cattle health Supported by

NADIS Parasite Forecast – December 2017

Use of meteorological data to predict the prevalence of parasitic diseases

Temperature: October 2017 (as °C Above/Below Regional Average 1961-1990)

Temperature: August - October 2017 (as °C Above/Below Regional Average 1961-1990)

Rainfall: October 2017 (as % Above/Below Regional Average 1961-1990)

Rainfall: August – October 2017

(as % Above/Below Regional Average 1961-1990)

October started changeable and was dominated by a warm moist south-westerly, with some higher than average temperatures at times, ending up colder by the end of the month. The UK mean temperature was 11.3 °C, with mean maximum temperatures generally 1 to 2°C above average. It was a drier than average except in western Scotland, Cumbria and north Lancashire, with below average rainfall amounts in southern and eastern areas.

December Parasite Forecast/Update The most recent version of this monthly parasite forecast may be accessed at www.nadis.org.uk.

Regional Weather

(based on Met Office figures)

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

Liver Fluke Warning! • The summer has been one of the wettest on record

with higher than average rainfall during the months of May through to October in many parts of GB. Based on cumulative wetness scores, the NADIS fluke forecast is is predicting a “high-risk” of fluke infection in North, West and central Scotland, West Wales and Cornwall this autumn; with “medium-risk” in Eastern Scotland, and parts of North and South West England.

• Most of Central and Eastern regions of England are forecast to be at “low-risk”.

• More localised and detailed fluke-risk information

will be available through veterinary practices participating in the new NADIS parasite control initiative.

SHEEP Fluke • If a second triclabendazole (TCBZ) treatment was

required in the higher, acute fluke-risk regions of the country, the next fluke treatment can probably be delayed until January.

• Where TCBZ- resistance has been confirmed, or is suspected, then consider the use of either closantel or nitroxynil, which are active on later immature (> 6-7week-old) and adult fluke.

• Chronic liver disease in sheep, due to the presence of adult fluke, peaks in the late winter/early spring.

• Affected sheep may show a progressive loss of condition, weakness, lowered appetite, emaciation, a brittle open fleece, the development of anaemia characterised by pale mucous membranes, and submandibular oedema (“bottle jaw”).

• Albendazole and oxyclozanide are effective from 10-14 weeks post infestation and can be used when treatment is recommended to remove adult flukes only.

• Subsequent spring treatments will remove any surviving adult flukes and prevent pasture contamination by fluke eggs reducing the risk of disease later in the year.

• Farmers in lower fluke-risk regions of the country should consult their veterinary surgeon about fluke control measures.

• If sheep have not been treated, then faecal samples from around 10 animals will identify patent fluke infection acquired during the autumn and indicate the need to treat the flock.

Parasitic gastroenteritis (PGE) • Outbreaks of trichostrongylosis in store and

replacement lambs, and even gimmers, are a risk during mild, wet weather in November and December.

• Continue to monitor worm egg counts on pooled faecal samples where there is a risk of disease.

• Heavy infestations cause black foetid diarrhoea (black scour) and rapid weight loss.

Trichostrongylosis in store and replacement lambs is a risk if mild wet weather continues through November.

Scab and Lice • Sheep scab is typically encountered during the

autumn/winter months from September to April.

• The symptoms of both sheep scab and lice can be similar and so diagnosis is important before deciding on treatment.

• Sheep scab, caused by the presence of psoroptic mites (Psoroptes ovis), can be very debilitating with significant loss of condition, secondary infections and eventually deaths if not treated.

• Remember also that sheep scab is notifiable in Scotland.

• Infestation leads to severe pruritus, wool loss, restlessness, biting and scratching of infested areas, weight loss, reduced weight gain and in some cases, death.

• The fleece is wet, sticky, yellow, and frequently contaminated with dirt from the hind feet.

• Typically, after eight weeks’ infestation, or so, the hair loss on the flanks may extend to 20 cm diameter surrounded by an area of inflammation and serum exudation. The skin is often thrown into thickened corrugations.

• For scab diagnosis, tests available include examining skin scrapings from suspect sheep or an antibody test on blood samples.

Early sheep scab – rubbing causing breakage of wool over the chest wall.

Advanced sheep scab –there is extensive fleece loss over the chest which is wet, sticky and yellow at the edges due to serum leaking from the skin.

• Lice infestations are commonly mistaken for sheep scab and vice versa.

• Like sheep scab, louse populations are highest in sheep during late winter with spread occurring by close contact with other sheep.

• Infestations of chewing lice are widespread in most sheep flocks. Sucking lice are not a problem in the UK.

• Louse burdens are most severe in lean/emaciated sheep, are highly visible, and often highlight poor stock management.

• The welfare implications of heavy louse infestations must not be forgotten.

Scab and Lice Treatments • Sheep scab can be controlled by administration of

an injectable macrocyclic lactone (ML). Treatment requires either a single, or repeat injection 7-10 days apart, depending of the product and active ingredient.

• Because of the growing concern over selection of ML-resistance in roundworms and scab mites, it is important to ensure scab treatments are given correctly following current SCOPS guidelines.

• Louse infestations can be controlled with topical application of high cis cypermethrin or deltamethrin, but these are most effective on shorn sheep.

• Plunge dipping in diazinon controls both scab and lice infestations.

Louse populations are highest during late winter and may cause disrupted feeding patterns, fleece damage/loss, and self-inflicted trauma.

Poor flock husbandry - heavy louse infestation affecting a hogg in poor condition. Immediate treatment is necessary for welfare reasons.

CATTLE

Liver Fluke • Out-wintered cattle in high fluke-risk areas may

need dosing in December, but because acute fluke is rare, consideration should be given to using either alternatives to TCBZ.

• Seek advice and base treatments on local farm conditions and the NADIS fluke forecast.

• Cattle dosed on housing with these alternative treatments should be tested for the presence of adult fluke, or given a second treatment to ensure all fluke are removed.

• The interval between housing and testing or re-treatment will depend on the product used. For closantel or nitroxynil the re-treatment interval is 6-7 weeks; and for oxyclozanide or albendazole the interval is 10-12 weeks.

• Faecal egg counting, serum or bulk milk ELISA testing, and slaughterhouse liver reports, are practical methods of detecting fluke-infected herds.

Don’t forget to try the interactive quiz

Slaughterhouse liver reports are a practical means of detecting fluke-infected herds and flocks. The mature flukes are found in the bile ducts but are shown here on the surface of the liver.

Parasitic Gastroenteritis • Autumn-born beef calves should not require

anthelmintic treatment at housing.

• Ostertagia larvae ingested by susceptible yearling stock during the autumn may have arrested their development and overwinter (as early L4) in the abomasal (stomach) wall.

• These arrested larvae resume their development in late winter/spring and can cause outbreaks of acute scour with subsequent death (type 2 ostertagiosis).

• Susceptible animals exposed to contaminated pastures during the later grazing season will be at risk from type 2 ostertagiosis unless they have been dosed with an anthelmintic effective against inhibited larvae, at housing, or at least before late winter.

• Lungworm outbreaks decrease significantly from November onwards. Coughing in unvaccinated susceptible cattle at pasture before housing, or in undosed stock after housing, should be investigated for the presence of lungworm larvae in faecal samples.

Autumn-born beef calves should not require anthelmintic treatment at housing.

Lice • Low burdens of lice are very common in the coats

of cattle during the winter months and should not necessarily be considered of significance.

• However, populations can increase rapidly causing intense itching, or anaemia if sucking lice are present.

• Both chewing and sucking lice are found on cattle in the UK.

• Heavy louse infestation may be a sign of other underlying conditions and an indicator of ill-thrift.

• A range of pour-on or spot-on synthetic pyrethroid products (containing alpha-cypermethrin, deltamethrin or permethrin) and macrocyclic lactones are commonly used.

• Injectable macrocyclic lactones are effective against sucking lice but may have only limited activity against chewing lice.

• It is advisable to use the product most suitable for the time of year and cattle management system cattle involved.

• See the COWS website at www.cattleparasites.org.uk for details of products available.

Heavy louse infestations in cattle may be a result of ill-thrift or other underlying causes.

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.

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

Supporting Knowledge Transfer