Efficacy of ivermectin administered via sustained-release bolus against gastrointestinal nematodes in cattle

Gary L. Zimmerman From the College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 (Zimmerman, Mulrooney) and Merck, Sharp & Dohme Research Laboratories, PO Box 2000, Rahway, NJ 07065 (Wallace).

Search for other papers by Gary L. Zimmerman in
Current site
Google Scholar
PubMed
Close
 PhD, DVM
,
Donna M. Mulrooney From the College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 (Zimmerman, Mulrooney) and Merck, Sharp & Dohme Research Laboratories, PO Box 2000, Rahway, NJ 07065 (Wallace).

Search for other papers by Donna M. Mulrooney in
Current site
Google Scholar
PubMed
Close
 BS
, and
Dennis H. Wallace From the College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 (Zimmerman, Mulrooney) and Merck, Sharp & Dohme Research Laboratories, PO Box 2000, Rahway, NJ 07065 (Wallace).

Search for other papers by Dennis H. Wallace in
Current site
Google Scholar
PubMed
Close
 DVM

Click on author name to view affiliation information

SUMMARY

Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P < 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was > 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.

SUMMARY

Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P < 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was > 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 54 54 9
PDF Downloads 31 31 2
Advertisement