Farm Ireland
Independent.ie

Saturday 27 May 2017

How to break the parasite cycle when housing cattle

Housing is one of the key times to break this cycle and treat cattle against the most common internal and external parasites.
Housing is one of the key times to break this cycle and treat cattle against the most common internal and external parasites.

Gordon Peppard

Many cattle will be housed over the coming weeks. Coming off grass, these animals bring with them a large burden of parasites.

These parasites can cause a lot of damage, reducing performance by causing diarrhoea, a drop in appetite, increasing the risk of both viral and bacterial pneumonia, and thereby affecting feed intake, reducing weight gain.

If untreated, these parasites can then reinfect pastures after turnout and keep the cycle going.

Housing is one of the key times to break this cycle and treat cattle against the most common internal and external parasites.

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Treating parasites

There are many different options to control stomach/intestinal worms. Ensure when choosing your product that it will cover all stages of worms, including the inhibited stomach worms. Levamisoles (yellow drenches) are only effective against adults.

Many of the combination products used to control stomach worms will also control lungworms, but be sure to check the label for efficacy against various stages of parasites and consult your vet if you are unsure.

When treating for the external parasites like lice and mange, make sure to treat on the same day as they are contagious and if treated on separate days, they will reinfect the treated animals.

Difficulty with liver fluke

Many products will only control liver fluke at the adult stage, therefore it is critical to understand the different stages of the liver fluke life-cycle. The liver fluke has three distinct stages, going from early immature to immature, followed by adult fluke.

In order to get a correct dosing strategy, it is important to use the correct product at the right time. For example, going in too early with a dose after housing will not kill early immature fluke and within a matter of weeks, they will have developed into adults.

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If the flukicide used at housing is only effective against older immature and/or adult liver fluke, then dosing six to 10 weeks later is recommended to kill the early immature fluke that have now become adults. A faecal sample could help to see if fluke are present.

Pictured at the Teagasc/AHI/DAFM/Meat Industry Ireland 'Beef Health Check Event' in Gorey Co Wexford is Veterinarian Michael Bergin demonstrating the presence of liver fluke in cattle livers Photo Roger Jones.
Pictured at the Teagasc/AHI/DAFM/Meat Industry Ireland 'Beef Health Check Event' in Gorey Co Wexford is Veterinarian Michael Bergin demonstrating the presence of liver fluke in cattle livers Photo Roger Jones.

Delaying treatment for liver fluke until at least six weeks after housing, will ensure most of the fluke should have developed to at least the immature/adult stage and will be susceptible to the treatment.

The main problem with this method is that the fluke could have caused a lot of damage and loss of weight gain in the intervening period.

Dosing with a triclabendazole two to three weeks after housing should kill all the stages of fluke present and therefore a follow-up treatment should not be necessary.

Triclabendazole is the only active ingredient to work against all three stages of the liver fluke. Beware of long withdrawal periods of between 50 to 60 days on flukicides, particularly if you plan to slaughter animals out of the shed.

As cattle cannot pick up worms and liver fluke while they are indoors, an effective treatment programme shortly after housing keeps them free of these parasites until they return to pasture or are slaughtered.

Indo Farming