2 June 1995

Anthelmintic cuts – false economies

EXTENSIVE grazing systems should reduce the impact of parasitic worms on hill flocks, but the best stockmen know that an effective control programme is still vital.

This is especially true where away wintering of ewe lambs, and the use of common grazings, increase the risk of worm-free sheep leaving the farm clean and returning infected.

Huw Jones, a tenant on 621ha (1500 acres) of very difficult upland in the Elan Valley, Powys, believes attempting to cut anthelmintic bills is a false economy.

"Fluke should not be a problem on this acidic land, but I believe I have to dose against any immature flukes the away wintered sheep may bring back," Mr Jones says. Sheep treated against all types of worms which graze the shared open mountain can also be exposed to challenge from worms carried by sheep from other farms.

Spring and autumn

The 1400 Welsh Mountain ewes run at Nant-y-Beddau are dosed in spring and autumn with the combined stomach worm/liver fluke drench Superverm. A 5-litre pack costs £100 and will treat 625 ewes, so the two annual doses cost about 32p/ewe.

Lambs get up to four doses of anthelmintic. White drench products are alternated to cut the chances of resistance building up. The first treatment is in May, when the lambs begin making significant use of pasture, the second at shearing in mid-July. Wether lambs are drenched again in September, when they are moved to lowland pastures for finishing.

Any that are still around at dipping in October and likely to be carried into winter are given a fourth dose. Ewe lambs get their fourth drench before going to away wintering. The lamb products used also contain selenium and cobalt and cost around £125 for 10 litres, and doses vary between 2.5ml and 5ml according to lamb weight.

"At our stocking rate some people might argue that were are over cautious, but I am convinced that the routine is cost effective. On a hard farm like this unthriftiness can be the result of several different factors, I want to be sure that worms are not a serious factor."