INVESTIGADORES
FERNANDEZ Alicia Silvina
congresos y reuniones científicas
Título:
Internal parasites in dairy heifers born in autumn in Buenos Aires province (Argentina). I. Effect on body weight gain, II. Epidemiological study
Autor/es:
FIEL, CÉSAR; FERNÁNDEZ, ALICIA SILVINA; RODRÍGUEZ, EDGARDO; FUSÉ, LUIS; SOMINSON, PABLO
Lugar:
Cambridge
Reunión:
Conferencia; 17th International Conference of the World Association for the Advancement of Veterinary Parasitology; 1993
Resumen:
This work was carried out between Dec 1991 and Nov 1992 in Tandil county. The production trial involved 50 Holando Argentina female calves born in autumn, approximately 5-6 months of age, allocated to three groups: Group 1, monthly anthelmintic treatment; Group 2, tactical anthelmintic treatment (March, June, August, October); Group 3, untreated control. The anthelmintic used was Fenbendazole at a dose rate of 5 mg/kg. The total body weight gains and daily body weight gains in the 341 days of trial were: Group 1, 157.3 and 0461 kg; Group 2, 149.5 and 0.438 kg; Group 3, 115.5 and 0.339 kg. The eggs per gram (epg) counts for Group 3 reached a peak in June and decreased markedly until the end of the trial. The identified helminth genera by faecal cultures were Ostertagia, Cooperia, Haemonchus, Trochonstrongylus, and Oesohagostomum. In the epidemiological study, at the slaughter of the tracer calves that grazed the pasture successively for one month in order to determine the pasture infectivity, the higher adult worm burden was found in July. The main geenra were Ostertagia in January, April-July, and September; Haemonchus in February, March, and July; and Cooperia in December-March, and July. Ostertagia showed inhibition mainly in spring (October and November). Tehre were few Dictyocaulus viviparus, the high number of this genus was detected in August.