Anthelmintic effect of rafoxanide against immature Fasciola hepatica in calves
Presidente, P.J.; Knapp, S.E.
American Journal of Veterinary Research 33(8): 1603-1610
1972
ISSN/ISBN: 0002-9645 PMID: 5047119 Document Number: 56038
For five consecutive days a dose of 200 metacercariae was given by stomach tube to 30 steers aged 2-3 months. In each group of 10 animals, half received F. hepatica cultured from ovine sources and half received F. hepatica from a bovine source. Leucocyte counts revealed eosinophilia in all groups by day 33. Antitoxin and vaccine against clostridial infection were administered after the death of two calves on days 22 and 25. On day 47, groups 2 and 3 were drenched with rafoxanide at doses of 7.5 and 10 mg/kg, respectively; there were no signs of toxicosis. Weight gain was not affected by treatment. Mean faecal egg count on day 89 was 4 and 0.5, respectively, in groups 2 and 3, compared to 16.6 and 51.7 in the group 1 calves infected from ovine and bovine sources, respectively. At slaughter (days 92-96) mean liver weight in groups 2 and 3 was 2.5 and 2.6 kg, compared to 2.8 and 3.7 kg in group 1 calves infected from ovine and bovine sources, respectively. Typical lesions were found in all livers. The mean number of flukes in groups 2 and 3 was 102, compared to 203 and 246 in group 1 calves infected from ovine and bovine sources, respectively. There were indications of treatment being more effective against the bovine-source flukes in group 3. In group 1 calves, the mean length of fluke tended to be greater, and flukes from bovine sources were longer than those from ovine sources. The efficacy of treatment in both groups was 59%, but at the higher dose recovery was more uniform. There was insufficient time before P.M. examination to determine the fate of flukes surviving the treatment.