1 September 1995

Beware buying-in disease with the stock

PRODUCERS buying in stores should try to eliminate unwelcome diseases as soon as lambs arrive, says Dr John Vipond, senior sheep specialist at the Scottish Agricul-tural College.

The most prevalent disease risks are scab and worms. The former can be eradicated only by plunge dipping or two injections of ivermectin 14 days apart. "If farmers choose to inject, lambs must be kept separate from sheep already on the farm until they have had the second dose," says Dr Vipond.

"Farmers concerned about introducing worm resistance on to their farms should use oramec or ivermectin-based drenches. There is likely to be higher resistance of worms to drenches in lambs bought in from lowland farms, as they have been dosed more often than hill-bred stock. On the other hand hill lambs have been more exposed to fluke, so they need a combined fluke and worm drench."

Trace element deficiency is another area for consideration, he says. Cobalt deficiency is the most prevalent, especially in lambs which have been raised in the Highlands and on land which is short of the mineral. In such cases Dr Vipond advises a cobalt drench, which he says is more efficient in the long-term than relying on the new pasture and farm to correct the deficiency. Any lamb suffering lack of cobalt was likely to be smaller than its peers and have a poorer appetite.

With grass in short supply now and in the foreseeable future, there would be a temptation for some producers to consider grazing cereal stubbles. But Dr Vipond warns there is always a danger lambs will suffer from acidosis. "When they eat too many wheat or barley heads which are lying in the stubble rumen pH drops and that can lead to fatal blood acidosis."

He suggests restricting access to cereal stubbles to half an hour for the first few days, otherwise lambs would over-indulge.

When the rain does arrive and if the weather is still warm there will be a tremendous flush of new growth and this lush autumn grazing can also lead to problems, such as scouring. Dr Vipond advises producers offer lambs water and hay to fill their bellies before turnout. This management tip also applies to any lambs which havebeen on a long journey.

Secure fencing, especially for hill lambs, is also essential. "Most are only familiar with native grasses, so do not immediately graze stubble or highly digestible perennial ryegrasses. They prefer to eat around the headlands for the first few days and hence put fencing under considerable strain. It is, therefore, vital to check your fencing before turning out lambs." &#42