Worms and flukes attack sheep, goats and cattle. Animals gain less weight, give less milk and may die.
Roundworms, Tapeworms and Liver Flukes
Roundworms cause animals to lose body condition. The animal loses appetite and grows more slowly or stops growing. A roundworm can lay 5 000 or 10 000 eggs per day inside the body of the animal. An animal with three thousand female worms may contaminate a pasture with several million eggs daily for 20 months. The worms hatch on the ground and can survive for months before entering another animal as it grazes.
Signs of tapeworms include a rough coat, pot belly, diarrhoea and anaemia. The animals have a good appetite, but they do not gain weight and may even lose weight. When there are many worms, the animals look out of condition, and get other diseases more easily.
Liver flukes make scars in the liver. The bile ducts become large. The liver becomes fibrous, and bad to eat. When you slice up the liver you find many flukes going all through the liver. After liver fluke eggs hatch, the tiny flukes need to penetrate and develop into a Limnea snail, which is found in wet areas. The snail releases larger flukes which are eaten by animals while grazing. Sheep and cattle can die within a few days. But normally the animals become weak over a few months.
How to Control Liver Flukes, Roundworms and Tapeworms
Treat calves for worms after weaning, and graze them on clean pasture. Treat animals for worms at the beginning and end of each rainy season. Young animals, sheep and goats are more susceptible and should be treated not just at the beginning and end of the rains, but also in between. In countries with long rainy seasons, you may need more treatments, but never more than four times a year. Leave 4 to 8 weeks between treatments.
To control liver flukes, especially in wet or marshy highland areas, animals should be treated every three months or so. Always watch for sick animals. Treat all animals that have worms. Some dealers sell fake drugs, so buy drugs from a shop you trust. The products come in many sizes. You can apply drugs as a bolus or a drench. Ask your veterinarian for more specific advice.