Disposition of oxfendazole in goats and efficacy compared with sheep.
The disposition of intraruminally administered oxfendazole (OFZ) in goats was studied at 5, 10 and 20 mg kg-1. The area under the plasma concentration with time curve (AUC) increased with increasing dose but at a declining rate. AUC was lower after intra-abomasal compared with intraruminal administration. OFZ was less effective against drug resistant Trichostrongylus colubriformis in goats than in sheep but was of similar efficacy against drug resistant Haemonchus contortus in both host species. In the same experiment peak plasma levels of OFZ in goats were about half those in sheep given the same dose. Of 70 goats tested in the field, total rumen bypass occurred in 12 per cent and partial bypass in 67 per cent. Lower systemic availability due to bypass would be expected to reduce further anthelmintic efficacy in goats. From the results of these experiments a dose rate of 10 mg kg-1 is recommended for goats. When given at this rate as a divided dose at 12 hourly intervals over 24 hours, OFZ was significantly more effective than a single dose in reducing egg counts.
Sangster
N C
NC
Department of Veterinary Pathology, University of Sydney, New South Wales, Australia.
Rickard
J M
JM
Hennessy
D R
DR
Steel
J W
JW
Collins
G H
GH
D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001562:Benzimidazoles / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D005260:Female; D015511:Goat Diseases / Q000188:drug therapy; D006041:Goats / Q000378:metabolism*; D006188:Haemonchiasis / Q000188:drug therapy / Q000662:veterinary; D008297:Male; D012756:Sheep / Q000378:metabolism*; D012757:Sheep Diseases / Q000188:drug therapy; D014253:Trichostrongylosis / Q000188:drug therapy / Q000662:veterinary; D014254:Trichostrongylus / Q000187:drug effects
D000969:Antinematodal Agents; D001562:Benzimidazoles; C011030:oxfendazole