Efficacy of topically administered doramectin against eyeworms, lungworms, and gastrointestinal nematodes of cattle.
OBJECTIVE
To evaluate efficacy of topically administered doramectin against eyeworms, lungworms, and gastrointestinal nematodes of cattle.


METHODS
400 cattle (20 cattle in each of 20 trials).


METHODS
Trials were conducted in North America; natural and experimentally induced infections were used. In each trial, cattle were allocated randomly to control (placebo [saline [0.9% NaCl] solution at 1 ml/10 kg of body weight] or untreated; n = 10) or doramectin-treated (500 microg/kg of body weight; 10) groups. Treatments were applied in a single passage along the midline of the back, from the withers to the tailhead. Cattle were euthanatized > or =14 days after treatment, and worm burdens were determined by use of standard techniques.


RESULTS
Efficacy of doramectin was > or =95.3% against adults of Thelazia gulosa, T skrjabini, Dictyocaulus viviparus, Haemonchus contortus, H placei, Ostertagia lyrata, O ostertagi, Trichostrongylus axei, Bunostomum phlebotomum, Capillaria spp, Cooperia oncophora, C pectinata, C punctata, C spatulata, C surnabada, Nematodirus spathiger, Strongyloides papillosus, T colubriformis, Oesophagostomum radiatum, and Trichuris spp. Efficacy was 95.1% against fourth-stage larvae of D viviparus, H placei, O lyrata, O ostertagi, T axei, C oncophora, C punctata, C spatulata, C surnabada, N helvetianus, T colubriformis, O radiatum, and Trichuris spp. In addition, efficacy against inhibited fourth-stage larvae of O ostertagi and Ostertagia spp was > or =98.1%.


CONCLUSIONS
A single topical application of doramectin pour-on was efficacious against a broad range of nematode species in cattle.
Marley
S E
SE
Pfizer Central Research, Groton, CT 06340, USA.
Illyes
E F
EF
Keller
D S
DS
Meinert
T R
TR
Logan
N B
NB
Hendrickx
M O
MO
Conder
G A
GA
D000287:Administration, Topical; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy*; D004022:Dictyocaulus Infections / Q000188:drug therapy; D015822:Eye Infections, Parasitic / Q000188:drug therapy / Q000662:veterinary; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D008174:Lung Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary; D009348:Nematoda / Q000187:drug effects; D009349:Nematode Infections / Q000188:drug therapy / Q000662:veterinary*
D000871:Anthelmintics; D007559:Ivermectin; C084101:doramectin