The A to Z of internal parasites in cattle

Internal parasites can cause a loss of production and even death if severe enough. Integrated parasite management is essential for effective control. Janine Ryan reports.

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For centuries, farmers have been waging war against internal and external parasites.

Internal parasites, at their worst, can cause severe damage to a herd or flock, resulting in fatalities and leading to economic losses.

At best, internal parasites are a nuisance that can lead to a drop in production and negatively impact animals’ welfare. Moreover, parasites, whether internal or external, are a scourge on all farmers, regardless of whether they produce cattle, sheep, goats, horses, chickens, or pigs.

In this article, we take a look at the common internal parasites of cattle. Our list is by no means exhaustive, and should not be used as an alternative to seeking medical attention for animals that are infected with internal parasites. We also provide tables of the common internal parasites of sheep, goats, horses, chickens and pigs.

WIREWORM

Seven of the most common internal parasites of cattle include wireworm (Haemonchus placei), brown stomach worm (Ostertagia ostertagi), black scour worm (Trichostrongylus spp.), small intestinal worm (Cooperia spp.), liver fluke (Fasciola hepatica), and rumen fluke (Paramphistomum spp.).

While wireworm primarily impacts cattle, it never exclusively targets cattle, and sheep and goat farmers should similarly be wary of this parasite.

Wireworm is a roundworm, which resides in the abomasum (‘fourth stomach’) of cattle. Infected cattle pass wireworm eggs in their faeces, which hatch into larvae that develop on the land.

Other cattle then ingest infective L3 larvae (the infective stage of larvae’s life cycle) while grazing, which mature into adults in the abomasum, feeding on blood. Wireworm is most prevalent in the summer rainfall region of South Africa.