Registro Completo |
Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
Data corrente: |
30/08/2016 |
Data da última atualização: |
03/10/2016 |
Autoria: |
DONALD, A. D.; MORLEY F. H. W.; WALLER, P. J.; AXELSEN, A.; DONNELLY, J. R. |
Título: |
Availability to grazing sheep of gastrointestinal nematode infection arising from summer contamination of pastures. |
Ano de publicação: |
1978 |
Fonte/Imprenta: |
Australian Journal of Agricultural Research, v. 29, n. 1, p. 189-204, 1978. |
DOI: |
10.1071/AR9780189 |
Idioma: |
Inglês |
Conteúdo: |
Abstract: In two successive years, separate phalaris-subterranean clover pasture plots near Canberra were contaminated with nematode eggs by grazing with naturally infected sheep in each of the summer months (December, January, February) and the first month of autumn (March). At intervals until mid- to late winter, the availability of infection on pasture was estimated by grazing with worm-free 'tracer' lambs which were subsequently slaughtered for worm counts.
Summer rainfall in both years was above average. Tracer counts of Haemonchus contortus and Ostertagia, Trichostrongylus and Nematodirus spp. per l08 eggs per hectare remained high during summer, with evidence that migration of larvae to the herbage could continue for at least 2 months after contamination. Rates of decline in tracer worm counts over the autumn and winter did not differ between years, and from an assumed maximum 2 months after contamination in each of the summer months, were fastest from December and slowest from February contamination. These rates were similar for all genera on December-contaminated plots, but on January and February plots, Ostertagia spp. declined more slowly. H. contortus numbers fell sharply in early autumn to be low by the end of May. By mid July there would be few larvae of all genera available on pastures contaminated in December and January, but this is less certain on February-contaminated pastures, especially for Ostertagia spp. Implications for the control of nematode infections in sheep by anthelmintic treatment and grazing management are considered. MenosAbstract: In two successive years, separate phalaris-subterranean clover pasture plots near Canberra were contaminated with nematode eggs by grazing with naturally infected sheep in each of the summer months (December, January, February) and the first month of autumn (March). At intervals until mid- to late winter, the availability of infection on pasture was estimated by grazing with worm-free 'tracer' lambs which were subsequently slaughtered for worm counts.
Summer rainfall in both years was above average. Tracer counts of Haemonchus contortus and Ostertagia, Trichostrongylus and Nematodirus spp. per l08 eggs per hectare remained high during summer, with evidence that migration of larvae to the herbage could continue for at least 2 months after contamination. Rates of decline in tracer worm counts over the autumn and winter did not differ between years, and from an assumed maximum 2 months after contamination in each of the summer months, were fastest from December and slowest from February contamination. These rates were similar for all genera on December-contaminated plots, but on January and February plots, Ostertagia spp. declined more slowly. H. contortus numbers fell sharply in early autumn to be low by the end of May. By mid July there would be few larvae of all genera available on pastures contaminated in December and January, but this is less certain on February-contaminated pastures, especially for Ostertagia spp. Implications for the control of nematode infecti... Mostrar Tudo |
Palavras-Chave: |
Nematóide gastrointestinal. |
Thesagro: |
Haemonchus Contortus; Helminto gastrintestinal; Infecção; Nematóide; Ovino; Pastejo; Verminose. |
Thesaurus Nal: |
Grazing; Nematode control; Nematodirus; Ostertagia; Sheep; Trichostrongylus. |
Categoria do assunto: |
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Marc: |
LEADER 02566naa a2200349 a 4500 001 2052050 005 2016-10-03 008 1978 bl uuuu u00u1 u #d 024 7 $a10.1071/AR9780189$2DOI 100 1 $aDONALD, A. D. 245 $aAvailability to grazing sheep of gastrointestinal nematode infection arising from summer contamination of pastures. 260 $c1978 520 $aAbstract: In two successive years, separate phalaris-subterranean clover pasture plots near Canberra were contaminated with nematode eggs by grazing with naturally infected sheep in each of the summer months (December, January, February) and the first month of autumn (March). At intervals until mid- to late winter, the availability of infection on pasture was estimated by grazing with worm-free 'tracer' lambs which were subsequently slaughtered for worm counts. Summer rainfall in both years was above average. Tracer counts of Haemonchus contortus and Ostertagia, Trichostrongylus and Nematodirus spp. per l08 eggs per hectare remained high during summer, with evidence that migration of larvae to the herbage could continue for at least 2 months after contamination. Rates of decline in tracer worm counts over the autumn and winter did not differ between years, and from an assumed maximum 2 months after contamination in each of the summer months, were fastest from December and slowest from February contamination. These rates were similar for all genera on December-contaminated plots, but on January and February plots, Ostertagia spp. declined more slowly. H. contortus numbers fell sharply in early autumn to be low by the end of May. By mid July there would be few larvae of all genera available on pastures contaminated in December and January, but this is less certain on February-contaminated pastures, especially for Ostertagia spp. Implications for the control of nematode infections in sheep by anthelmintic treatment and grazing management are considered. 650 $aGrazing 650 $aNematode control 650 $aNematodirus 650 $aOstertagia 650 $aSheep 650 $aTrichostrongylus 650 $aHaemonchus Contortus 650 $aHelminto gastrintestinal 650 $aInfecção 650 $aNematóide 650 $aOvino 650 $aPastejo 650 $aVerminose 653 $aNematóide gastrointestinal 700 1 $aMORLEY F. H. W. 700 1 $aWALLER, P. J. 700 1 $aAXELSEN, A. 700 1 $aDONNELLY, J. R. 773 $tAustralian Journal of Agricultural Research$gv. 29, n. 1, p. 189-204, 1978.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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