INVESTIGADORES
FERNANDEZ Alicia Silvina
congresos y reuniones científicas
Título:
Effect of Duddingtonia flagrans against Ostertagia ostertagi in grazing cattle
Autor/es:
FERNÁNDEZ, ALICIA SILVINA; LARSEN, MICHAEL; HENNINGSEN, ELSE; NANSEN, PETER; GRØNVOLD, JØRN; BJØRN, HENRIK; WOLSTRUP, JENS
Lugar:
Copenhagen
Reunión:
Conferencia; 17th International Conference of the World Association for the Advancement of Veterinary Parasitology; 1999
Institución organizadora:
Danish Centre for Experimental Parasitology
Resumen:
The nematode-trapping fungus Duddingtonia flagrans has been shown to reduce the number of Ostertagis ostertagi L3 on herbage in plot trials. Two field trials were conducted to test this under grazing conditions with a high and low risk of parasitic exposure, respectively. In each of the two trials thirty calves experimentally infected with O. ostertagi were divided into three comparable groups and allocated to three similar paddocks. Two of the three groups received fungal material (high or low dose) once per day during the initial two months. The third group remained as an untreated control group. Faecal, blood, and herbage samples were collected and animals were weighed every month from May to September. Under the high risk mamagement, the number of L3 on pasture was reduced and calves were protected from clinical disease using D. flagrans at the high dose-level. In the low risk situation the parasitism of the animals seemed not to be severe, and no conclusive effect of the fungus could be detected even at the high dose-level. The present study showed that different factors affect the efficacy of the applied biological control agent, such as stocking rate and number of overwintering infective larvae. Future studies should be conducted to elucidate the optimum dose-level of the fungal material to be used under different grazing conditions.