National Animal Disease Information Service

(NADIS)

Parasite Forecast

April 2013

About this webinar

• The parasite forecast is published monthly

and written by specialist veterinary surgeons

• Based on detailed Met office data

• Sponsored by Merial Animal Health

• Supported by EBLEX, HCC and QMS

Meteorological Data

Temperature

Rainfall

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

Temperature Rainfall Above/below regional averages (1961-1990)

Disease Focus:

Nematodirus

Life cycle

Key facts

Control

Development

to worms in

abomasum

Eggs

passed in

dung

Develop

to L3

larvae

Infective L3

migrate up

grass blades

Grazing

lambs ingest

L3 larvae

Nematodirus:

Life Cycle

~15 days

but

delayed if

cold

10-12 days

Nematodirus: Key Facts

May and June usually see the greatest

amount of disease

Clinical signs include profuse diarrhoea

Disease is mainly caused by worm larvae

Nematodirus: Control

• Avoid grazing lambs on pasture used for

young lambs in the previous year

• If not possible, early lambs may require

drenching before the end of April

• Use BZ (group 1) products

Parasitic

Gastroenteritis (PGE)

Risks

Treatment

PGE: Risk • Overwintered larvae picked up by late

pregnant or lactating ewes

• Egg development will be quicker as temperatures increase through March/April

– Eggs passed by ewes maintains infectivity of the pasture

PGE: Treatment

• Target treatments to

thinner or multiple

bearing ewes

• Leave at least 10% of

the flock un-treated!

Other diseases

Coccidiosis

Chronic liver fluke

Cattle nematodes

Tick-borne fever

Coccidiosis • Significant risk in April

• Adverse weather

conditions cause:

– Poor colostrum

– Poor grass growth

– Extended housing

Chronic Liver Fluke

Cattle Nematodes • Dairy calves and autumn-born suckler calves will need

treatment in 1st season unless on safe grazing – Or ‘dose and move’ at mid-summer

– Lungworm is best controlled using vaccination (‘Huskvac’)

• Worm problems are usually greater in wet summers – but Autumn disease can be seen following a dry summer

Ectoparasites: Ticks • ‘Tick-borne fever’ transmitted by ticks

• Abortion in pregnant ewes

• Secondary infections in young lambs

– This ‘tick pyaemia’ causes abscesses

– Control ticks using pour-on acaricides before lambs go on to contaminated pastures

• Tick pyaemia can

cause:

– Paralysis

– Joint ill

– Abscesses under

the skin

Questions

• Please click on the link below to answer a

short quiz and print your Advanced

Livestock Skills certificate