Roundworms of Cattle

Roundworms (nematodes) are the most important group of internal parasites affecting cattle in Australia and can significantly impact production efficiency.

Roundworms have a direct life cycle, but most require a period on pasture in a non-parasitic form. Roundworms are mostly a problem for cattle under 18 months of age.

The most important roundworms in cattle in Australia are:

• Barber’s pole worm (Haemonchus placei)
• Small brown stomach worm (Ostertagia ostertagi)
• Small intestinal worm (Cooperia species)
• Nodule worm (Oesophagostomum radiatum)

Other roundworms found in cattle include:

• Stomach hair worm: Trichostrongylus axei
• Black scour worm: Trichostrongylus species
• Thin-necked intestinal worm: Nematodirus species
• Lungworm: Dictyocaulus viviparus
• Hookworm: Bunostomum phlebotomum
• Large-mouthed bowel worm: Chabertia ovina
• Threadworm: Strongyloides species
• Whipworm: Trichuris species
• Eye worm: Thelazia species
• Other nematodes: ascarid worm: Toxocara vitulorum and gullet worm: Gongylonema species

Most of these worms share the basic roundworm life cycle but some have additional stages inside the cattle.