Internal Parasites of Ruminants

Small worms can infect sheep, cattle, goats and buffalo, and live in the animal’s gut, lungs, liver and blood. These worms are called parasites and the animal they live in is called the host. The parasite feeds off the host which becomes weak, loses weight, develops disease and can die.

What is a parasite?

A parasite lives in or on another animal and feeds on it. All animals and humans can become infected with parasites. Ruminants can be infected with several types of worms.

Roundworms are small, often white in colour, and look like threads. Different roundworms are found in all parts of the gut and the lungs.

Tapeworms are long, and flat and look like white ribbons. They consist of many segments and live in the intestine.

Flukes are flat and leaf-like, they live in the liver. Schistosomes are small and worm-like, both infect animals kept on wet, marshy ground as their eggs develop in water.

Infection of Parasites in Animals

The roundworms, flukes and schistosomes lay eggs which pass out of the animal in the dung onto the pasture. Tapeworms produce eggs in the segments which break off and pass out in the dung. Animals become infected when they graze the pasture. Parasites feed on the food in the gut and on the blood of the host. The animal becomes weak and loses weight or does not gain weight. It can develop diarrhoea, which in sheep makes the wool wet and attracts flies.

Eventually the host becomes so weak that it dies. Young animals are especially affected by parasites.