Grass seed lesions

General description

  • Grass seeds reported at the abattoir refer to seeds found in the carcass (in the muscle).
  • At slaughter, seed contaminated carcases require trimming, which can result in significant reductions in carcase weight.
  • Carcases may be downgraded and export markets put at risk.


  • As lambs/sheep graze on or walk through seedy pastures/areas, seeds are collected in the wool and then enter the body within days.
  • The greatest risk period for picking up seeds is October to January in most regions.
  • A number of plant species cause grass seeds problems including:
    • Barley grass
    • Brome grass
    • Chilean needle grass
    • Erodium
    • Silver grass
    • Spear grass
    • Wire grass

Different species are present in different areas. Find out which species may be in your area.

Clinical signs

  • Reluctance to move, particularly young sheep and lambs.
  • Eye, ear, face and mouth injuries which may result in blindness, lameness or loss of appetite.
  • Flystrike secondary to grass seeds penetrating the skin.
  • Rough, discoloured or cotted wool (from biting or rubbing).


  • Seeds will be seen visually when the fleece is opened along the neck, jowl, and belly wool.
  • At slaughter, if the carcass is skinned, you will see the extent of seed penetration on the underside


  • No treatment available against grass seeds.
  • Seed-infested sheep can be relocated to seed-safe pastures but can remain contaminated for over two years, although the level of contaminating seeds is reduced rapidly over the first six months.


Seed management strategies:

  • Grazing management (stocking density, feedlotting, grazing rotation)
  • Livestock management (time of lambing, shearing)
  • Agronomic management (pasture manipulation, sown fodder crops, fodder conservation)
  • Target market and time of turn-off

Learn more

Complete Guide: Winning against seeds - Management tools for your sheep enterprise

Seed contamination of carcases and management strategies

QLD - Avoiding impacts on sheep from grass seeds

DAFWA - Managing grass seeds in sheep