NADIS Parasite Forecast - March 2014
Use of meteorological data to predict the prevalence of parasitic diseases
The UK mean temperature was 4.8 °C, which is 1.1 °C above the 1981-2010 average. The UK overall received 151% of average rainfall making it the third wettest in the series. A broad region from east Devon to Kent and up to the central midlands received well in excess of 200 % and some more localised regions were closer to three times the average. Parts of eastern Scotland were also similarly wet, with in excess of twice the normal rainfall. The region of south east and central south England beat its January rainfall record by a large margin and was the wettest calendar month for that region in a series from 1910. It was also the wettest January in the England and Wales precipitation series that is based on a much smaller network of rain gauges, but extends back to 1766, with January 1948 being the closest comparable January 2014. It was not wet everywhere though and parts of northern Scotland were significantly drier than average. There was a general division in sunshine across the country; despite being so wet the south east of the UK was sunnier than average whereas the north-west was duller than average. The UK overall received 95 % of average sunshine hours. (www.nadis.org.uk).
March Parasite Forecast/Update
The most recent version of this monthly parasite forecast may be accessed at www.nadis.org.uk.
PARASITIC GASTROENTERITIS (PGE)
- Parasite control should be planned on an individual farm basis.
- "Clean grazing" for sheep at turnout is defined as last year's pastures grazed by cattle or re-seeded pastures
Sheep - Clean grazing
- The principle aim around lambing time is to minimize the contamination of pastures by eggs passed by adult parasites in the gut of the ewes. These eggs hatch and develop into infective larvae causing disease in lambs.
- This "peri-parturient rise" in faecal egg production by ewes can be controlled by a short-acting anthelmintic before turnout onto clean pasture.
- In order to avoid undue selection for anthelmintic resistance, Sustainable Control of Parasites in Sheep (SCOPS) recommends that this dose is targeted and that not all ewes are dosed such that some anthelmintic-susceptible parasites are carried over onto the clean pasture. (EBLEX 2014 leaflet 'The BRP Cattle and Sheep Parasite Control Guide http:// www.eblex.org.uk/returns/)
- This targetted anthelmintic regimen should include:
- Gimmers and young ewes
- Ewes nursing twins and triplets
- Ewes in low body condition
Ewes nursing singles may not need anhelmintic treatment before turnout onto clean grazing.
Ewes nursing multiple litters and those in poor condition should be treated before turnout onto clean grazing.
Sheep - Contaminated pastures
- Ewes turned onto contaminated pastures should be treated with a persistent anthelmintic to prevent immediate re-infection of the ewes with larvae from the pasture.
Be aware and plan ahead for Nematodirosis control
- Nematodirosis caused considerable production losses in young lambs in late spring/early summer on many farms in 2013.
- Use clean grazing wherever possible to remove the risk of disease.
Nematodirosis affecting lambs grazing contaminated pasture - note only the lambs are scouring, the ewes are unaffected.
Watch out for chronic liver fluke in sheep and beef cattle
- Chronic liver fluke in sheep peaks in the late winter/early spring.
- Diagnosis of liver fluke is suspected in sheep showing signs of weight loss, bottle jaw and reduced production. Most flukes present in sheep will be adults so fluke egg counts at this time will indicate infestation and the need for treatment.
Liver fluke egg.
- Additional diagnostic methods your veterinary surgeon may consider include blood biochemistry (raised GGT, low albumin and raised globulin) and post mortem examination of any fatalities.
- Un-dosed beef cattle grazing potentially infected pastures, should either be treated or checked for the presence of fluke eggs in faeces.
Plan ahead to prevent lungworm disease in cattle
Lungworm disease is typically seen in grazing cattle from July onwards (see below).
- Vaccination of cattle over two month-old requires two doses four weeks apart, with the second dose at least two weeks before turnout or weaning.
- Cattle with a history of respiratory disease should not be vaccinated.
- Plan now with your veterinary adviser to prevent lungworm disease in cattle.
- Lungworm disease is typically seen in grazing cattle from July onwards
- There are several anthelmintic control strategies that can be used on set-stocked systems using including depot injection and strategically-timed injections, and either pulse release or slow delivery boluses.
- Anthelmintic control strategies for lungworm will also aid control of gut parasites, particularly ostertagiosis.
Lungworms in the large airways of a yearling stirk causing death.
Watch out for sheep scab
Neglected case of sheep scab.
- Veterinary investigation of intense itching and wool loss is essential because heavy louse infestations can look like sheep scab. Some flocks may have concurrent sheep scab and louse infestations.
- Sheep scab causes serious production losses including lower lamb birth weights and increased lamb mortality when ewes are affected during late pregnancy.
- Seek veterinary advice regarding the best treatment option.
- Review biosecurity measures if either infestation occurs on the farm. Lice and sheep scab are most commonly introduced onto farms by infested sheep.
Local farm conditions may vary so consult your veterinary surgeon. Parasite control should be part of your veterinary health plan
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