Dr Jeff Cave, Senior Veterinary Officer
Worms and scours can be a significant problem in weaners and lambing ewes with the limited feed and cold stress of winter.
Winter conditions provide ideal conditions for the survival of worm larvae on pastures, and feed may also be short. Sheep that are nutritionally stressed and in light condition grazing short pastures are likely to be affected by worms and scouring.
Worms should be considered in all ill-thrifty or scouring sheep, regardless of when the sheep were last drenched.
To help establish whether worms are the cause, you should consider the following:
- the sheep's nutrition, including the feed availability, supplemental feeding, and stocking rate
- the sheep's class and condition, including their body condition score
- the drench program, including the product/s used and date/s drenched, particularly the time since the last treatment.
To know for sure, faecal samples from at least 5 affected and 5 non-affected sheep should be submitted for worm egg counts.
To help manage worms in sheep during winter:
- provide adequate feed for weaners and lambing ewes on low worm pastures such as those prepared by smart grazing over summer, those previously grazed by cattle, or those used for cropping
- weanersand lambing ewesneed to be in a condition score of around 2.5. If lighter, they will need preferential treatment and feeding
- check worm egg counts by Wormtest (samples from 10 representative sheep) every 4 to 6 weeks through winter
- confirm that the drench worked by Wormtest at the time of drenching and 10 to 14 days later.
- check worm egg counts in lambing ewes about 4 weeks before lambing.
