Worms can live in the sheep's gut for many months. Some species can live exposed on the ground for six months or longer in favourable conditions. Black scour worm is the most common type of internal parasite causing infection in Australian sheep flocks.
Rest periods (i.e. the interval between consecutive grazing in a paddock by sheep) long enough to have allowed enough time for many of the larvae on the pasture to die. Typically these need to be 40–80 days depending on temperature (see life cycle page and 'Factors contributing to paddock contamination with worms')
Once larvae have developed to L3 stage they can survive living on your pasture for months. In cooler weather (0-25oC) larvae from both horse and cattle/sheep worms will happily survive on your pasture for up to nine months.
Once ingested by a host, this larva has the ability to get out of the egg, hatch in the small intestine and migrate to different organs. These infective larvae (or "infective eggs") may remain viable in soil for two years or longer.
Traditionally, people have been worming lambs when clinical signs appear (i.e. scouring, wasting, etc.) or just every three weeks.
Heavy stocking rates and insufficient pasture rest periods contribute to the incidence of parasitic disease in sheep and lambs. Internal parasites tend to be much less of a problem under range-type conditions where sheep do not graze the same pasture twice in the same grazing season.
There are two ways to mitigate this risk and make sure both resistant and susceptible worms go with sheep while still capitalising on the clean pasture. Either treat them a few days before moving (leaving them on the old pasture during that time), or leave a small number (10%) of the sheep untreated.
Some parasites go away on their own, especially if you have a healthy immune system and maintain a balanced diet. However, talk to a healthcare provider if you have signs of a parasitic infection. They can make an official diagnosis and help prevent the spread of the parasite to others.
Even though you cannot see them, large populations of parasites can thrive in your soil for weeks and months.
Worms emerge at night, when the air is cool and moist. They feed on decaying organic matter on the soil surface.
Worms will eat a wide variety of organic materials such as paper, manure, fruit and vegetable waste, grains, coffee grounds, and ground yard wastes. While worms will eat meat and dairy products, it is best not to feed these materials or oily foods to worms, due to potential odor and pest problems.
Tapeworm segments can be seen in the feces of sheep and goats. They have a white, grain-like appearance. Adult worms, often up to a meter or more in length, can be expelled and passed in the environment. Tapeworm eggs can be seen in sheep and goat feces, using the standard worm count procedure.
Once inside a sheep's intestine, the larvae moult again and mature into adult worms capable of producing eggs. In favourable weather conditions, the life cycle of sheep intestinal worms is about three weeks. It shortens as temperatures rise and lengthens as days get cooler.
They burrow during the day—typically keeping close to the surface—capable of digging down as deep as 6.5 feet. The worm's first segment contains its mouth. As they burrow, they consume soil, extracting nutrients from decomposing organic matter like leaves and roots.
As well as keeping soil healthy, worms can help clean up contaminated land by enhancing 'bioremediation' – the process by which micro-organisms consume and break down environmental pollutants converting them to non-toxic molecules.
By their activity in the soil, earthworms offer many benefits: increased nutrient availability, better drainage, and a more stable soil structure, all of which help improve farm productivity. Worms feed on plant debris (dead roots, leaves, grasses, manure) and soil.
Some beetles are predators of earthworms, especially larger ground beetles (Carabidae) and rove beetles (Staphylindae) such as the devil's coach horse (Ocypus olens). Centipedes are also known predators of earthworms and although it may seem unlikely there are even reports of spiders eating earthworms.
You'll likely need to give your doctor a stool sample for a few months to make sure all the worms are gone.
The worms will die after 6 weeks so provided you do not swallow any new eggs then no new worms will grow to replace them. Strict attention to hygiene should be sufficient.
Many scientists agree that worms tend to use soaked soil days as migration days. They can't travel as fast while burrowing tunnels under the ground, and it's too dry above ground on rain-free days for them to survive. So, a soaking rain allows them to slither to the surface and move gracefully on the wet ground.
Signs include scours/diarrhoea, soiled tails or pale gums. Worm infestations can result in a failure to thrive and, in more serious cases, cause death. Sheep in particular may fail to move about in the wet conditions, resulting in a considerable build-up of worms in a short period of time.
There are four components of an effective worm control program. They are drenching, grazing management, nutrition and breeding worm resistant sheep. Drenching alone will not resolve a worm problem. Too frequent drenching may reduce the sheep's immunity to worms and increase the problem of drench resistant worms.
Overdosing sheep or lambs with drench or incorrect pre or post drenching management can be fatal so it is important to consider how you drench as well as 'when' and 'what with'. Key drenching principles include: Always read the product label for both dosage and safety information.