Ostertagia Flashcards
Where Is ostertagia found?
The abomasal mucosa
= causative agent of PGE
Describe type 1 ostertagiosis
Seen in dairy replacement calves at the end of the first grazing season
Due to the ingestion of large numbers of L3 in July
July - September (typically August) - green watery diarrhoea and poor weight gain
High morbidity, low mortality
More common presentation
Describe type 2 ostertagiosis.
Seen in yearling calves in the late winter / spring, following their first grazing season
Hypobiosed larvae emerge from the mucosa
Low morbidity, high mortality
Diarrhoea, hypoalbuminaemia, anaemia and weight loss
What is the pathogenesis of ostertagiosis?
Worms emergence from the gastric glands of the abomasum and cause:
Loss of the glandular function of the abomasum
Protein losing enteropathy
= profuse watery diarrhoea
What parasite is the main contributor to PGE in cattle?
Ostertagia ostertagi
Can ostertagia overwinter?
Yes
L3 larvae survive on the pasture and are in ingested in May
(No disease at this stage)
Overwintered larvae die off in June
Calves establish a patent infection and excrete eggs on pasture
Peak levels occur on the pasture in mid July
= type 1 ostertagiosis in August / September
Larvae in the gastric glands begin to hypobiose in Autumn
Larvae development resumes in late winter / early spring
= type 2 ostertagiosis
Why do Spring born beef calves not tend to get ostertagiosis?
Overwintered larvae have died off by the time they are turned out in June / July
Graze with immune mothers who provide MDA and ingest some larvae
When might Autumn born beef calves be at risk of ostertagiosis?
When they are turned out in the spring without their mothers
How can you manage ostertagiosis in a herd?
Clean pasture - not grazed by cattle in the past 12 months
Safe pasture - safe by the beginning of June
Rotate the land with crops or stock species
