Tuesday 14 January 2014

An," Integrated parasite control strategy" : Sheep and goats, worms and flukes.

Indoors and free of new fluke and worm infections but its only temporary
All grazing livestock; cows, sheep and goats are all infected with worms to some extent. A heavy worm burden and poor nutrition will kill the animal. At lower levels of infection growth rate and milk production are affected.

Infective worm larvae are ingested with herbage, the larvae then attache themselves to the gut, suck blood, reproduce and shed eggs in the faeces. The eggs develop to the infective larval stage and the cycle is repeated. For the last 40 years we have been able to control the problem with drugs and grazing management. But now worms have become resistant to many of the drugs and we have to work out a worm control strategy for each individual farm that minimises the resistance problem and gives effective control. Its a headache because so many factors have to be taken into account. Commercial goat milk  producers keep their animals in yards year round because of the risk of infection and the need to withdraw milk for consumption for up to eight weeks after treatment.

Our, "integrated parasite control strategy" begins with housing. Once the ewes have been indoors for 5 or 6 weeks all of the immature flukes should be in the liver and can be killed with a flukicide. They won't pick up any more until they are outside again. In late pregnancy the ewe's natural immunity to worms is low and the worm burden increases so we will worm them just before lambing. The goats will be wormed as they kid.

Same parasites
That covers January until April. The next eight months, when the ewes are out grazing, are more complicated and difficult to plan for.

Goats and sheep are hosts to the same parasite species but because the goats tend to browse rather than graze the herbage they ingest is higher up and less likely to carry infective larvae.

An important part of the strategy will be to do faecal egg counts (FECs) for the goats to make sure that dosing is really necessary.

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