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Strategic Worm Control in Sheep

Wormy sheepOur practice is focused on herd and flock health and preventative management. Controlling internal parasites, especially in sheep, through advice and the supply of a range of drenches is one of our key services. We encourage producers to speak with our vets about developing parasite control programs designed for their property.

Refer to Liver fluke in sheep and cattle for information about fluke infestation.

Worm control strategies include:

  • Routine monitoring of worm burdens using regular faecal egg counts (FEC)
  • Effective drenching
  • Management choices aimed at reducing worm burdens, including attention to stocking density and pasture rotation
  • Breeding programs aimed at parasite immunity
  • Nutrition and disease control strategies that support the animal’s natural ability to fight worm infection
  • Developing knowledge about drench resistance on your property
  • When disease is evident, being proactive about identifying the cause – we have dedicated autopsy facilities as well as our pathology laboratory.

Common worms

The following internal parasites are the most common cause of ill-thrift, sickness and death in sheep flocks.

Barber’s pole worm (Haemonchus contortus)

  • Found in the 4th stomach (abomasum)
  • Severe infestation causes ill-thrift, poor condition, pale mucous membranes (gums, third eyelid), bottle jaw, death
  • Daily egg production per female worm = 5,000-15,000

Brown stomach worm (Teladorsagia circumcincta, previously Ostertagia)

  • Found in the 4th stomach (abomasum) and small intestine
  • Severe infestation leads to ill-thrift, scouring
  • Daily egg production per female worm = 100-200

Black scour worm (Trichostrongylus species)

  • Found in the 4th stomach (abomasum)
  • Severe infestation causes ill-thrift, poor condition, scouring, death
  • Daily egg production per female worm = 100-200

Thin-necked intestinal worm (Nematodirus species)

  • Found in the small intestine
  • Severe infestation causes scouring (young sheep)
  • Daily egg production per female worm = 50-100