Good worm control is essential for the success of all sheep flocks. From the moment lambs are turned out onto pasture they are at risk from developing a worm burden. Jess Clayton our resident SQP at Whitchurch tells us more.

A burden can cause decreased appetite, reduced growth rates, damage to the gut, impaired mineral retention and poor protein metabolism which reduces muscle growth and carcase quality.

There are several management factors to consider which can all assist in reducing lambs to worm burden exposure…

Safe vs High risk pastures

It is essential to access which of your pastures is likely to pose the most risk to this years new lambs and where possible avoid turnout onto these.

High RiskMedium RiskLow Risk
– Ewes and lambs
grazed in the previous

– High risk of
Nematodirus if
pasture carried ewes
and lambs in the
previous spring.

– Goats have grazed in the previous year.

– Store/ewe lambs
grazed the previous
– Grazed only by adult non-lactating sheep in the previous year.

– Grazed by ewes and
lambs in the previous spring, but then
conserved and
aftermath not grazed
by sheep (but still a
risk for Nematodirus!)
– New lays or forage

– Grazed by cattle or
cut for silage/hay in
the previous year (no

Group lambs by age

Keeping lambs in close age groups at turn out can make treatment decisions more accurate when based upon faecal egg counting to monitor levels. It also creates ease for deciding treatment products in light of withdrawal periods.

Mixed grazing

Where grazing options are limited, grazing after cattle can reduce pasture contamination. Cattle ingesting sheep parasites will be unable to complete their lifecycle, so no eggs will be passed out onto the pasture.

Grazing Quality

Lambs need good quality grazing to meet growth rates and in turn will create resilience to worms as the season progresses. Avoid grazing lambs on very low sward heights (2-3cm) to reduce their intake of infective larvae which are more concentrated at the base of the grass blades.

It is essential during turnout to use faecal egg counts to monitor numbers of worms in the lambs which will determine the need to treat, provide information about the levels of pasture contamination and determines if a treatment given has been effective. Contact us if you want more information!