Snowy Winter Could Offer Silver Lining

The icy, snowy winter weather that persisted through into 2010 might have seemed dire at the time, particularly for those famers that struggled to get out to feed livestock but Janssen Animal Health say this could be one cloud that really has a silver lining.

For several years now many sheep farmers have been battling against record fluke levels in their flocks which have resulted in ill thrift, anaemia, bottle jaw and reduced lambing percentages. But the sharp shock of low temperatures should be warmly welcomed say Janssen, as the cold could offer some respite by interrupting the parasite lifecycle. 

Fluke eggs deposited on pasture can survive for a time at low temperatures but adverse conditions can reduce survival and hatchability. This means that after a cold winter the main contribution to future infection is likely to be from infected animals passing eggs and the mud snail, which is an intermediate host, emerging from hibernation in spring to deposit infective cysts from May onwards. Cysts derived from these winter snails are much less significant in number than those from summer infected snails, partly because of snail mortality during the winter months. The harsher the winter, the fewer snails are likely to survive.

All of this means that farmers have a unique opportunity this spring to really get on top of their fluke problem. Pasture contamination this year is likely to be lower than in previous springs that have followed mild winters and by treating the flock with a spring dose of flukicide, it can be kept low. Closantel (Flukiver®) is the ideal choice for this spring treatment as it disrupts egg laying for 13 weeks – longer than any other flukicide1.

Janssen Animal Health has long championed the idea of strategic approaches to treatment that tackle fluke control in a more lasting way – one study showed additional strategic spring-summer dosing with closantel (Flukiver®) can clear the disease to near negligible levels within two years2.

While the individual approach on each farm may vary, it’s clear that this spring there is a distinct opportunity to tackle fluke seriously. For further information on developing a strategic response to fluke, farmers should talk to their vet or SQP this spring.

Flukiver® contains closantel Legal Category POM-VPS

Further information is available from Janssen Animal Health, 50-100 Holmers Farm Way, High Wycombe, Bucks, HP12 4EG Tel 01494 567555 Fax 01494 567556 Email:


  1. Sheep Farmer Jan / Feb 2007  22-23
  2. The Veterinary Record, Vol 127 No 18, 450-452 (1990)