Floods of rain raise fears over fluke problems
Liver fluke is usually a more important cause of economic loss on farms than rumen fluke, and should not be overlooked.
Most animals with rumen fluke do not have associated disease or adverse effects on performance.
However, it is expected that clinical cases of rumen fluke will occur on some farms this season.
In recent weeks, the Regional Veterinary Laboratories have reported some fatalities due to rumen fluke in cattle and sheep.
Grazing on waterlogged or previously flooded pastures is the highest risk factor for rumen fluke infection.
Rumen fluke tends to be a clinical problem in cattle (especially young animals) and sheep that have been exposed to large numbers of the immature parasite over a short period of time.
When is treatment for rumen fluke necessary?
Your own vet may advise on treatment for rumen fluke when clinical signs of severe diarrhoea and weight loss occur.
This diagnosis may be confirmed through laboratory evidence of significant infection, or post-mortem results if deaths occur.
Fatal cases have large numbers of immature rumen fluke in the small intestine.
It is important to send animals for post mortem soon after death for best results, because larvae detach from the intestinal lining very shortly after death.
If rumen fluke eggs are detected by faecal examination in healthy animals that are thriving well, you do not need to dose for rumen fluke, but are advised to observe stock closely for any emerging clinical signs of diarrhoea and/or severe weight loss.
Animals should only be treated if these clinical signs are seen.
Treatment options
Most of the drugs that control liver fluke do not kill rumen fluke.
Although not specifically licensed in Ireland for the treatment of rumen fluke, oxyclozanide is the only medicinal product on the Irish market that kills both mature and immature stages of this parasite; it is available in different products.
Oxyclozanide is not effective against immature liver fluke, but it will kill immature rumen fluke.
After treatment, cattle may occasionally show transient scouring and lack of appetite with an associated decrease in milk yield.
Current veterinary advice to prevent the development of resistance is to avoid the over-use of this flukicide.
Routine treatment for rumen fluke is rarely justified except on farms where severe clinical disease has been confirmed in the past.
Even in these cases, treatment should only be administered when clinical disease has been diagnosed, because this drug has no persistent effect against rumen fluke.
Close monitoring is essential on farms, and for the best advice on treatment and control options, you should consult with your own vet, who will also ensurethat any planned action will not overlook any necessary measures against liverfluke.
For more information refer to the AHI online leaflet, Rumen Fluke — The Facts, on the www.animalhealthireland.ie website.
