12 April 2002

Act against coccidiosis

By Hannah Velten

ALTHOUGH coccidiosis risks should be lower in lambs this year with the recent improvement in weather and fewer movement restrictions, producers should remain on their guard.

Independent sheep consultant Lesley Stubbings says a modest coccidiosis outbreak, with 5% mortality in young lambs, can cost £12/ewe in a lowland flock (see table).

Creep-fed lambs which survive an outbreak after treatment can need an extra 4kg of feed to finish and prices are lowered because they take longer to finish and some poor conformation.

For producers not using coccidiostat in feed, treating lambs at a certain age or on a pre-set date as a routine can be a waste of time and money because over-treated lambs can fail to build up immunity.

"Under normal conditions, lambs pick up low numbers of oocysts from a very early age and they develop active immunity. This means that by the time oocyst levels rise sharply, because of greater numbers of lambs at pasture, they have enough immunity to cope."

Therefore, Ms Stubbings urges producers to hold back on treatment until it is needed. But this does require careful monitoring of 4-8 week old lambs, although older lambs can also suffer.

Flocks at high risk of an outbreak include those lambing early and rearing lambs intensively, those densely stocked, over-used nursery paddocks, or where lambs of different ages are mixed. Lambs also need to receive adequate colostrum and any other disease present, such as nematodirus, will increase risks of coccidiosis.

"At the first sign of coccidiosis, take a faecal sample and seek vet advice on treating lambs, ensuring the whole batch of lambs on that pasture are treated. Spot treatment of scouring lambs will not control the outbreak. When lambs also have nematodirus there is no point in treating for coccidiosis without treating that too."

Ms Stubbings also warns that more cases of coccidiosis have been reported in older lambs in the past few years.

"When lambs fail to develop immunity at a young age, they can go down with coccidiosis in later life. Lack of exposure can be caused by treating lambs too early against infection, so they have little chance to build immunity."

UK producers often mistake the scouring, ill-thrift and dehydration caused by the infection, as parasitic gastro-enteritis. "When worming fails, they blame anthelmintic failure or resistance. Many lambs can die before vet advice is sought and they are treated correctly," she says. &#42

Allowing lambs to build up immunity to coccidiosis should cut treatment costs, says Lesley Stubbings.


Impact/100 ewes Total loss (£) Reduction in gross margin (£/lamb)

Eight deaths @ £40.70/lamb less creep feed saved (90% x £5.20) 288.16 1.75

10% increase in creep use (59p x 157 lambs) 81.64 0.49

Less 20p/kg on sale price 580.90 3.52

Treatment costs (all lambs) 235.50 1.43

Total 1186.20 7.19