Brown stomach worm
| Brown stomach worm | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ostertagia ostertagi | ||||||||||||
| ( Stiles , 1892) |
The brown stomach worm ( Ostertagia ostertagi ) is a parasite that can mainly attack cattle, but also sheep and goats. It belongs to the group of roundworms (nematodes).
In 1890 Robert von Ostertag discovered the most common stomach worm in Europe, Ostertagia ostertagi .
distribution
In intensive cattle farming, gastrointestinal worm infestation is widespread in all parts of the world. The humid grazing areas of the temperate climatic zones, such as the coastal, lowland and alpine areas in Germany, are particularly affected. There are strong seasonal and age-related differences in the infestation, with an average of 30–80% of all cattle affected.
features
The worm reaches a length of 6–12 mm, its German name it received because of its brownish thread-like appearance. The females produce thin-shelled, oval, 60–100 × 30–60 µm eggs with 16–32 furrowed spheres.
Life cycle
The worm eggs are excreted into the outside world with the faeces. After a minimum development period of 5–7 days, at a temperature of 5–12 ° C, the 0.5–1 mm long larvae hatch from the worm eggs. They feed on the faecal components of the host. The larvae moult twice without shedding the second shell.
The now infectious larvae live on residual nutrients. They survive for several months to a year and overwinter in large numbers on the pastures. In April and May, however, most of the larvae from the previous year die. Despite a comparatively fast development outside at an outside temperature of approx. 25 ° C, the infection larvae often remain in the dung heap for weeks. This enables them to survive dry periods well before they either actively move out of the manure by migrating within a radius of 50 cm or passively by smearing or flooding the manure to the pasture plants and thus to new hosts.
Shortly after ingestion by the host, the larvae reach the fundus glands of the abomasum and form small elevations of the mucous membrane with typical funnel-shaped indentations. In summer, the lifespan of the Ostertagia ostertagi (summer Easter tagiosis) is only a few weeks, while the larvae take a break from development from October until the end of winter.
Clinic, diagnosis
The adult worms and the larvae living on the mucous membrane cause inflammation of the mucous membrane. Possible signs of illness can therefore be significant digestive disorders, which become noticeable through reduced feed consumption, diarrhea and developmental arrest, as well as apathy , frequent lying down, unsteady gait, severe gastroenteritis or a poorly filled rumen . The persistent diarrhea leads to a disturbance in the water balance, which the animal first tries to compensate by increasing water intake but later develops into pronounced desiccosis .
The detection of gastrointestinal worm eggs is carried out using the flotation method . Another possibility is a faecal examination using the McMASTER method or a percentage differentiation of the parasites involved by breeding larvae. With Easter tagiosis, the pepsinogen levels in the blood are also increased.
Prevention, control
To ensure optimal control, the degree and spread of the worm infestation within the herd should be clarified before starting treatment. Thereafter, changes in husbandry and / or feeding (e.g. switching to dry feeding) or the animals should be divided into several treatment groups. The aim is to expel immature and mature worm stages from the gastrointestinal tract, to prevent reinfection and to carry out symptomatic treatment of the diseased animals.
The treatment is carried out orally, by back infusion or as medicinal feed for all animals in a pasture group. A well-tolerated anthelmintic (e.g. ivermectin , fenbendazole ) should be used in a medium dose (in severely ill animals). A new entry is necessary after a recovery time of 1–3 weeks.
Taxonomy
Robert von Ostertag described the species in 1890 as Strongylus convolutus - a name that Kuhn had given in 1829 to another worm known today as Torynurus convolutus , which is why Charles Wardell Stiles (1867–1941) renamed the brown stomach worm in 1892 to Strongylus ostertagi . Brayton Howard Ransom (1879-1925) made the species then in 1907 the type of the new genus Ostertagia .
swell
- Gerrit Dirksen, Hans-Dieter founder, Matthaeus Stöber: Internal medicine and surgery of cattle . 5th edition, Parey at MVS, Stuttgart 2006, ISBN 978-3-8304-4169-4