Small redworms are common because of their ability to
become resistant to wormers.
Small redworms commonly comprise more than 95% of the eggs
excreted in the dung. They
are about 0.5- 1.5cm long and live in the large intestine.
They are greyish white in colour but appear red when
feeding on blood. Left uncontrolled they can reproduce in huge numbers. Without an
effective preventive worming programme pasture is likely to become heavily
contaminated with potentially dangerous levels of Infective larvae.
Once eaten, the larvae of small redworms burrow into the
gut lining until they mature.
They then emerge from the gut wall and move back into the
gut to become egg-laying adults .They have a relatively short life cycle which is complete in about
10 weeks, but in the right conditions can be as short as 6 to 8 weeks.
As autumn approaches an increasing number of larvae become
encysted in the gut wall where they stop developing and 'hibernate'. These
are called 'inhibited larvae' and can make up a large proportion of the
population in the gut wall at this time of year .
When the larvae emerge (typically December-May) they can
cause severe damage to the gut leading to diarrhoea, rapid weight-loss,
colic and sometimes death within a very short period of time.
Small redworms can affect horses of any age.
