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The epidemiology of helminth infections of growing sheep in Argentina's western pampas
- Source :
- International Journal for Parasitology. 25:489-494
- Publication Year :
- 1995
- Publisher :
- Elsevier BV, 1995.
-
Abstract
- Seasonal population trends of helminth parasites of growing lambs were investigated over 4 years. Successive worm-free lambs were grazed together with untreated lambs for 20–30 days and then slaughtered for helminth counts 2 weeks after their removal from pasture. Likewise untreated lambs from the same flock were slaughtered from 2 to 15 months of age for worm counts in the same way as tracer lambs. The predominant parasites were Haemonchus, Nematodirus and Trichostrongylus. Haemonchus contortus was found to be of major importance and the flock aquired massive worm burdens from summer to mid-autumn. Minimum burdens were seen from winter to early spring and maximum L4 stages were found from mid-autumn to early winter. Nematodirus burdens increased from December with a peak in late summer and then decreased to low values. Maximum larval availability was in autumn to early winter. Trichostrongylus (mainly T. colubriformis ) populations increased in autumn and peaked in June–July, while the highest larval availability was in autumn. The minor genera recovered were Ostertagia, Cooperia, Trichuris, Oesophagostomum and Moniezia. Dictyocaulus, Chabertia and Teladorsagia were noted occasionally and liver flukes were not detected. No important and pathogenic numbers of L4 stages were seen and all predominant species were able to survive over summer or winter in pasture.
- Subjects :
- Veterinary medicine
Trichostrongylus
animal diseases
Population
Argentina
Helminthiasis
Sheep Diseases
Helminths
parasitic diseases
Animals
Moniezia
Intestinal Diseases, Parasitic
education
Parasite Egg Count
Oesophagostomum
education.field_of_study
Sheep
biology
Ecology
Trichostrongylosis
biology.organism_classification
Survival Rate
Infectious Diseases
Haemonchus
Parasitology
Dictyocaulus
Nematodirus
Seasons
Flock
Helminthiasis, Animal
Haemonchiasis
Haemonchus contortus
Subjects
Details
- ISSN :
- 00207519
- Volume :
- 25
- Database :
- OpenAIRE
- Journal :
- International Journal for Parasitology
- Accession number :
- edsair.doi.dedup.....58039454135d1973d37901b71fd78a75